Search results for "nucleic acid"
showing 10 items of 810 documents
Adaptive trends of sequence compositional complexity over pandemic time in the SARS-CoV-2 coronavirus
2021
In the brief time since the outbreak of the COVID 19 pandemic, and despite its proofreading mechanism, the SARS-CoV-2 coronavirus has accumulated a significant amount of genetic variability through recombination and mutation events. To test evolutionary trends that could inform us on the adaptive process of the virus to its human host, we summarize all this variability in the Sequence Compositional Complexity (SCC), a measure of genome heterogeneity that captures the mutational and recombinational changes accumulated by a nucleotide sequence along time. Despite the brief time elapsed, we detected many differences in the number and length of compositional domains, as well as in their nucleot…
Genetic lesions associated with Muller's ratchet in an RNA virus
1996
The molecular basis of Muller's ratchet has been investigated using the important animal pathogen foot-and-mouth disease virus (FMDV). Clones from two FMDV populations were subjected to serial plaque transfers (repeated bottleneck events) on host BHK-21 cells. Relative fitness losses were documented in 11 out of 19 clones tested. Small fitness gains were observed in three clones. One viral clone attained an extremely low plating efficiency, suggesting that accumulation of deleterious mutations had driven the virus near extinction. Nucleotide sequence analysis revealed unique genetic lesions in multiply transferred clones that had never been seen in FMDVs isolated in nature or subjected to m…
Nalidixic acid-resistant V79 cells with reduced DNA topoisomerase II activity and amplification prone phenotype
1992
Spontaneously nalidixic acid-resistant lines (NAr lines) were selected from a V79 Chinese hamster cell line and phenotypically characterized. NAr lines showed an increased doubling time, a higher number of spontaneous SCE, and more interestingly, decreased DNA topoisomerase II activity. These lines were also cross-resistant to the eukaryotic topoisomerase II inhibitors etoposide and adriamycin, but showed the same level of sensitivity as the parental line to the DNA topoisomerase I inhibitor camptothecin. NAr lines were cross-resistant to other drugs, such as PALA, MTX and MPA, resistance to which has been shown to arise by amplification of the target genes. This last feature, together with…
Redox signaling in acute pancreatitis
2015
Acute pancreatitis is an inflammatory process of the pancreatic gland that eventually may lead to a severe systemic inflammatory response. A key event in pancreatic damage is the intracellular activation of NF-κB and zymogens, involving also calcium, cathepsins, pH disorders, autophagy, and cell death, particularly necrosis. This review focuses on the new role of redox signaling in acute pancreatitis. Oxidative stress and redox status are involved in the onset of acute pancreatitis and also in the development of the systemic inflammatory response, being glutathione depletion, xanthine oxidase activation, and thiol oxidation in proteins critical features of the disease in the pancreas. On th…
NATURAL SELECTION AND THE ORGAN-SPECIFIC DIFFERENTIATION OF HIV-1 V3 HYPERVARIABLE REGION
2004
The existence of organ-specific HIV-1 populations within infected hosts has been studied for many years; nonetheless results reported by different authors are somewhat discrepant. To tackle this problem, we used a population genetics approach to analyze previously published data from the V3 hypervariable region of the envelope env gene. Our results are compatible with a population subdivision by organs in 95% of individuals analyzed at autopsy. In addition, populations infecting the nervous system and testicles clearly appear as differentiated subsets of the so-called macrophage-tropic variants. Liver and kidney may harbor differentiated populations as well. Although it is widely accepted t…
Nucleic Acid Extraction. Quaderni del Dottorato di Ricerca in Oncobiologia Sperimentale: Tecniche e Procedure di Ricerca.
2008
Kinetic and equilibrium studies for the adsorption of acid nucleic bases onto K10 montmorillonite
2011
Abstract The kinetic of the adsorption of two nucleic acid bases, namely adenine (A) and cytosine (C), on K10 montmorillonite (MMT) clay has been investigated over a wide range of nitrogenous bases concentrations, by using the spectrophotometric method. The measurements have been performed at T = 25.0 °C and pH = 4.0 where adenine and cytosine exist both in their protonated and neutral forms. Preliminary to the kinetic data treatment, the adsorption isotherms have been gathered and, then, analyzed by using the Freundlich and the Dubinin–Radushkevich model. The obtained results allow to draw the conclusion that physisorption of adenine and cytosine on MMT occurs and the process is mainly gov…
The nucleic acid binding protein PcCNBP is transcriptionally regulated during the immune response in red swamp crayfish Procambarus clarkii
2015
Cellular nucleic acid binding proteins (CNBPs) represent a highly conserved protein family among vertebrates; they harbour seven tandem zinc finger repeats CCHC type and have been described as transcriptional and translational regulators. To date, there is little characterization of CNBP in invertebrates since its structure and function have been analysed solely in Drosophila melanogaster. However, no CNBP has been investigated in other arthropod systems. In an effort to isolate immune-related genes in Procambarus clarkii, a partial mRNA coding a zinc finger containing protein was found to be up-regulated during the response to white spot syndrome virus (WSSV) infection. The red swamp crayf…
Regeneration of total RNA purification silica-based columns
2010
Silica-based columns are largely used in RNA purification, allowing fast extractions and good yields of high quality nucleic acid, but their major limitation is the high cost. The reuse of such columns, although desirable, is not recommended because of residual amounts of material from the previous sample trapped in the column matrix, which might be released during further purification. Thus, recycling does need previous complete removal of any detectable RNA trace, but to date no protocol which allows decontamination and reuse is available.We report a very rapid decontamination procedure, based on treatment with warm alkaline solution containing Triton X-100, which ensures no RNA carry-ove…
Frequent chromosomal gains in recurrent juvenile nasopharyngeal angiofibroma.
2007
Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign tumor, mostly affecting adolescent males. Some patients develop recurrences after surgery independently of completeness of removal. Only very limited data concerning underlying chromosomal changes are available. We therefore analyzed samples of 22 JNAs, including six recurrences, with comparative genomic hybridization (CGH). Additionally, quantitative image cytometry was used for measurement of DNA aneuploidy in representative samples. Of the 13 primary JNAs without later recurrence, DNA gains were identified on autosomes in only two samples. Four patients with one or two recurrences were included in the study; for one of these, no…