scholarly journals Absolute quantification of viruses by TaqMan real-time RT-PCR in grapevines

2017 ◽  
Vol 47 (6) ◽  
Author(s):  
Thor Vinícius Martins Fajardo ◽  
Marcos Fernando Vanni ◽  
Osmar Nickel

ABSTRACT: The absolute quantification determines the absolute amount of a targeted nucleic acid expressed as a copy number or concentration. The knowledge of virus concentrations in commercial crops possesses high relevance to ensure a reliable diagnosis. The objective of this study was to perform an absolute quantification of five viruses in infected grapevines (Vitis spp.). Different known amounts of the standard sample (cloned viral cDNA or in vitro transcribed viral RNA) were quantified by TaqMan RT-qPCR. Based on these data, standard curves were generated plotting Ct values (threshold cycle) against the log of the standard sample amount. Infected grapevine samples were evaluated to determine virus titers, which were highly variable. This result may contribute to improve virus diagnosis by accurately quantifying virus titre variations in grapevines.

1978 ◽  
Vol 10 (5) ◽  
pp. 431-444 ◽  
Author(s):  
Silvio Parodi ◽  
Marco Cavanna ◽  
Pia Carlo ◽  
Claudia Bolognesi ◽  
Marina Picca ◽  
...  

1952 ◽  
Vol 50 (4) ◽  
pp. 471-490 ◽  
Author(s):  
S. Fazekas De St Groth

A technique is developed by which minimal changes in haemagglutinin inhibitors can be detected.It is shown that theinhibitor indexof normal human nasal secretions is 33·2 with a standard deviation of ±7·4. This value is independent of the donor, of the absolute amount of mucus collected, of the time of extraction, and of the period of storage.Minimal amounts of influenza viruses (less than one agglutinating dose) are capable of causing significant alteration in the inhibitor index upon interactionin vitrofor 60 min. at 37° C.


2019 ◽  
Vol 20 (11) ◽  
pp. 920-933 ◽  
Author(s):  
Lucía Gato-Calvo ◽  
Tamara Hermida-Gómez ◽  
Cristina R. Romero ◽  
Elena F. Burguera ◽  
Francisco J. Blanco

Background: Platelet Rich Plasma (PRP) has recently emerged as a potential treatment for osteoarthritis (OA), but composition heterogeneity hampers comparison among studies, with the result that definite conclusions on its efficacy have not been reached. Objective: 1) To develop a novel methodology to prepare a series of standardized PRP releasates (PRP-Rs) with known absolute platelet concentrations, and 2) To evaluate the influence of this standardization parameter on the anti-inflammatory properties of these PRP-Rs in an in vitro and an ex vivo model of OA. Methods: A series of PRPs was prepared using the absolute platelet concentration as the standardization parameter. Doses of platelets ranged from 0% (platelet poor plasma, PPP) to 1.5·105 platelets/µl. PRPs were then activated with CaCl2 to obtain releasates (PRP-R). Chondrocytes were stimulated with 10% of each PRP-R in serum-free culture medium for 72 h to assess proliferation and viability. Cells were co-stimulated with interleukin (IL)-1β (5 ng/ml) and 10% of each PRP-R for 48 h to determine the effects on gene expression, secretion and intra-cellular content of common markers associated with inflammation, catabolism and oxidative stress in OA. OA cartilage explants were co-stimulated with IL-1β (5 ng/ml) and 10% of either PRP-R with 0.75·105 platelets/µl or PRP-R with 1.5·105 platelets/µl for 21 days to assess matrix inflammatory degradation. Results: Chondrocyte viability was not affected, and proliferation was dose-dependently increased. The gene expression of all pro-inflammatory mediators was significantly and dose-independently reduced, except for that of IL-1β and IL-8. Immunoblotting corroborated this effect for inducible NO synthase (NOS2). Secreted matrix metalloproteinase-13 (MMP-13) was reduced to almost basal levels by the PRP-R from PPP. Increasing platelet dosage led to progressive loss to this anti-catabolic ability. Safranin O and toluidine blue stains supported the beneficial effect of low platelet dosage on cartilage matrix preservation. Conclusion: We have developed a methodology to prepare PRP releasates using the absolute platelet concentration as the standardization parameter. Using this approach, the composition of the resulting PRP derived product is independent of the donor initial basal platelet count, thereby allowing the evaluation of its effects objectively and reproducibly. In our OA models, PRP-Rs showed antiinflammatory, anti-oxidant and anti-catabolic properties. Platelet enrichment could favor chondrocyte proliferation but is not necessary for the above effects and could even be counter-productive.


1998 ◽  
Vol 26 (5) ◽  
pp. 629-634
Author(s):  
Emiliana Falcone ◽  
Edoardo Vignolo ◽  
Livia Di Trani ◽  
Simona Puzelli ◽  
Maria Tollis

A reverse transcriptase polymerase chain reaction (RT-PCR) assay specific for identifying avian infectious bronchitis virus (IBV) in poultry vaccines, and the serological response to IBV induced by the inoculation of chicks with a Newcastle disease vaccine spiked with the Massachusetts strain of IBV, were compared for their ability to detect IBV as a contaminant of avian vaccines. The sensitivity of the IBV-RT-PCR assay provided results which were at least equivalent to the biological effect produced by the inoculation of chicks, allowing this assay to be considered a valid alternative to animal testing in the quality control of avian immunologicals. This procedure can easily be adapted to detect a number of contaminants for which the in vivo test still represents the only available method of detection.


Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 66
Author(s):  
Zoltán László ◽  
Péter Pankovics ◽  
Gábor Reuter ◽  
Attila Cságola ◽  
Ádám Bálint ◽  
...  

Most picornaviruses of the family Picornaviridae are relatively well known, but there are certain “neglected” genera like Bopivirus, containing a single uncharacterised sequence (bopivirus A1, KM589358) with very limited background information. In this study, three novel picornaviruses provisionally called ovipi-, gopi- and bopivirus/Hun (MW298057-MW298059) from enteric samples of asymptomatic ovine, caprine and bovine respectively, were determined using RT-PCR and dye-terminator sequencing techniques. These monophyletic viruses share the same type II-like IRES, NPGP-type 2A, similar genome layout (4-3-4) and cre-localisations. Culture attempts of the study viruses, using six different cell lines, yielded no evidence of viral growth in vitro. Genomic and phylogenetic analyses show that bopivirus/Hun of bovine belongs to the species Bopivirus A, while the closely related ovine-origin ovipi- and caprine-origin gopivirus could belong to a novel species “Bopivirus B” in the genus Bopivirus. Epidemiological investigation of N = 269 faecal samples of livestock (ovine, caprine, bovine, swine and rabbit) from different farms in Hungary showed that bopiviruses were most prevalent among <12-month-old ovine, caprine and bovine, but undetectable in swine and rabbit. VP1 capsid-based phylogenetic analyses revealed the presence of multiple lineages/genotypes, including closely related ovine/caprine strains, suggesting the possibility of ovine–caprine interspecies transmission of certain bopiviruses.


2018 ◽  
Vol 54 (5) ◽  
pp. 427-444 ◽  
Author(s):  
R. D. Astumian

Fluctuations favour state B = (B,B′) based on kinetic asymmetry combined with moderate dissipation rather than state A = (A,A′) in which the absolute amount of dissipation is greater but where there is no kinetic asymmetry.


Author(s):  
Claudia Zech ◽  
Marco Evertz ◽  
Markus Börner ◽  
Yves Kayser ◽  
Philipp Hönicke ◽  
...  

The manganese deposition of an aged anode has been investigated with K-edge and L-edge NEXAFS to determine the manganese species. In addition, the absolute amount of manganese could be revealed with reference-free X-ray fluorescence analysis.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiaoyu Sun ◽  
Shunxiong Tang ◽  
Binbin Hou ◽  
Zhijun Duan ◽  
Zhen Liu ◽  
...  

Abstract Background Portal hypertension (PH) is the main cause of complications and death in liver cirrhosis. The effect of oral administration of octreotide (OCT), a drug that reduces PH by the constriction of mesenteric arteries, is limited by a remarkable intestinal first-pass elimination. Methods The bile duct ligation (BDL) was used in rats to induce liver cirrhosis with PH to examine the kinetics and molecular factors such as P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2) and cytochrome P450 3A4 (CYP3A4) influencing the intestinal OCT absorption via in situ and in vitro experiments on jejunal segments, transportation experiments on Caco-2 cells and experiments using intestinal microsomes and recombinant human CYP3A4. Moreover, RT-PCR, western blot, and immunohistochemistry were performed. Results Both in situ and in vitro experiments in jejunal segments showed that intestinal OCT absorption in both control and PH rats was largely controlled by P-gp and, to a lesser extent, by MRP2. OCT transport mediated by P-gp and MRP2 was demonstrated on Caco-2 cells. The results of RT-PCR, western blot, and immunohistochemistry suggested that impaired OCT absorption in PH was in part due to the jejunal upregulation of these two transporters. The use of intestinal microsomes and recombinant human CYP3A4 revealed that CYP3A4 metabolized OCT, and its upregulation in PH likely contributed to impaired drug absorption. Conclusions Inhibition of P-gp, MRP2, and CYP3A4 might represent a valid option for decreasing intestinal first-pass effects on orally administered OCT, thereby increasing its bioavailability to alleviate PH in patients with cirrhosis.


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