Publications by Julieta M Manrique
Journal of General Virology, 2015
Despite chronic hepatitis B virus (HBV) infection (CHB) is a leading cause of liver cirrhosis and... more Despite chronic hepatitis B virus (HBV) infection (CHB) is a leading cause of liver cirrhosis and cancer, HBV evolution during CHB isn't fully understood. Recent studies indicate that viral diversity progressively increases along the course of CHB and that some viral mutations correlate with severe liver conditions such as chronic hepatitis, cirrhosis and hepatocellular carcinoma. Using ultra deep sequencing (UDS) data from an intrafamilial case, we detected such mutations at low frequencies among three immunotolerant patients and at high frequencies in an inactive carrier. Furthermore, our analyses indicated that the HBV population from the seroconverter patient underwent great genetic changes in response to viral clearance. Altogether, these data point out a potential use of UDS for developing noninvasive biomarkers for monitoring disease changes over time or in response to specific therapies. In addition, our analyses revealed that viral clearance seems not to require viral effective population size to decline. A detailed genetic analysis of the viral lineages arisen during and after the clearance suggested that mutations at or close to critical elements of the core promoter (enhancer II, epsilon encapsidation signal, TA2, TA3 and DR1-HRE) might be responsible for a sustained replication. This hypothesis requires viral load declination to be explained by a constant clearance of virus-producing hepatocyte, consistent with the sustained progress towards serious liver conditions experienced by many CHB patients.
Biodiversity and Conservation, 2014
ABSTRACT Since the introduction of polymerase chain reaction (PCR) biodiversity study has been si... more ABSTRACT Since the introduction of polymerase chain reaction (PCR) biodiversity study has been significantly influenced by the chance of generating unprecedented amounts of molecular data. Although it is a robust technique, those applications requiring high sensitivity and reproducibility, that is PCR detection and quantitative PCR, can be negatively affected by PCR inhibition. This is particularly challenging for diverse kinds of samples included the environmental ones, which usually contain complex mixtures of a variety of inhibitory substances. The problem of PCR inhibition can be overcome, or ameliorated, by implementing adequate protocols of nucleic acids purification, internal controls and modern analytical approaches focused on PCR kinetics. Herein, we remark these procedures and describe the general techniques that can be used to optimize DNA extraction protocols for PCR applications. In addition, we show that PCR inhibition might have negative consequences in molecular studies of Didymosphenia geminata, an invasive microalga that have recently developed massive blooms in temperate regions worldwide, and provide general guidelines for dealing with this problem.
PLOS ONE, 2015
Bovine herpesvirus 4 (BoHV-4) is increasingly considered as responsible for various problems of t... more Bovine herpesvirus 4 (BoHV-4) is increasingly considered as responsible for various problems of the reproductive tract. The virus infects mainly blood mononuclear cells and displays specific tropism for vascular endothelia, reproductive and fetal tissues. Epidemiological studies suggest its impact on reproductive performance, and its presence in various sites in the reproductive tract highlights its potential transmission in transfer-stage embryos. This work describes the biological and genetic characterization of BoHV-4 strains isolated from an in vitro bovine embryo production system. BoHV-4 strains were isolated in 2011 and 2013 from granulosa cells and bovine oocytes from ovary batches collected at a local abattoir, used as "starting material" for in vitro production of bovine embryos. Compatible BoHV-4-CPE was observed in the co-culture of granulosa cells and oocytes with MDBK cells. The identity of the isolates was confirmed by PCR assays targeting three ORFs of the viral genome. The phylogenetic analyses of the strains suggest that they were evolutionary unlinked. Therefore it is possible that BoHV-4 ovary infections occurred regularly along the evolution of the virus, at least in Argentina, which can have implications in the systems of in vitro embryo production. Thus, although BoHV-4 does not appear to be a frequent risk factor for in vitro embryo production, data are still limited. This study reveals the potential of BoHV-4 transmission via embryo transfer. Moreover, the high variability among the BoHV-4 strains isolated from aborted cows in Argentina highlights the importance of further research on the role of this virus as an agent with the potential to cause reproductive disease in cattle. The genetic characterization of the isolated strains provides data to better understand the pathogenesis of BoHV-4 infections. Furthermore, it will lead to fundamental insights into the molecular aspects of the virus and the means by which these strains circulate in the herds.
Journal of Microbiological Methods, 2014
Didymosphenia geminata mats display few cells in relation to extracellular material and contain p... more Didymosphenia geminata mats display few cells in relation to extracellular material and contain polysaccharides and heavy metals that interfere with molecular studies. We describe an optimized DNA extraction protocol that help to overcome these difficulties. Our protocol outperformed five previously described DNA extraction techniques.
Virus Genes, 2012
A phylogenetic analysis of new Ostreococcus virus (OV) sequences from the Patagonian Coast, Argen... more A phylogenetic analysis of new Ostreococcus virus (OV) sequences from the Patagonian Coast, Argentina, and homologous sequences from public databases was performed. This analysis showed that the Patagonian sequences represented a divergent viral clade and that the rest of OV sequences analyzed here were clustered into six additional phylogenetic groups. Analyses of 18S gene libraries supported a close relationship of the Patagonian Ostreococcus host with clade A sequences described elsewhere, corroborating previous studies indicating that clade A strains are ubiquitous. Besides the Patagonian OV sequences, several phylogenetic groupings were linked to particular geographic locations, suggesting a role for allopatric cladogenesis in viral diversification. However, and in agreement with previous observations, other viral lineages included sequences with diverse geographic origins. These findings, together with analyses of ancestral trait trajectories performed here, are consistent with an evolutionary dynamics in which geographical isolation has a role in OV diversification but can be followed by rapid dispersion to remote places.
Veterinary Microbiology, 2012
Journal of Virology, 2013
Vaccine/challenge experiments that utilize live attenuated strains of simian immunodeficiency vir... more Vaccine/challenge experiments that utilize live attenuated strains of simian immunodeficiency virus (SIV) in monkeys may be useful for elucidating what is needed from a vaccine in order to achieve protective immunity. Derivatives of SIVmac239 and SIVmac239Δnef were constructed in which env sequences were replaced with those of the heterologous strain E543; these were then used in vaccine/challenge experiments. When challenge occurred at 22 weeks, 10 of 12 monkeys exhibited apparent sterilizing immunity despite a mismatch of Env sequences, compared to 12 of 12 monkeys with apparent sterilizing immunity when challenge virus was matched in its Env sequence. However, when challenge occurred at 6 weeks, 6 of 6 SIV239Δnef-immunized monkeys became superinfected by challenge virus mismatched in its Env sequence (SIV239/EnvE543). These results contrast markedly not only with the results of the week 22 challenge but also with the sterilizing immunity observed in 5 of 5 SIV239Δnef-immunized rhesus monkeys challenged at 5 weeks with SIV239, i.e., with no mismatch of Env sequences. We conclude from these studies that a mismatch of Env sequences in the challenge virus can have a dramatic effect on the extent of apparent sterilizing immunity when challenge occurs relatively early, 5 to 6 weeks after the nef-deleted SIV administration. However, by 22 weeks, mismatch of Env sequences has little or no influence on the degree of protection against challenge virus. Our findings suggest that anti-Env immune responses are a key component of the protective immunity elicited by live attenuated, nef-deleted SIV.
Journal of Virology, 2000
Journal of Photochemistry and Photobiology B: Biology, 2012
Electrochemistry Communications, 1999
Biosensors and Bioelectronics, 2004
AIDS Research and Human Retroviruses, 2001
Simian immunodeficiency viruses (SIVs) have an envelope (Env) glycoprotein with an unusually long... more Simian immunodeficiency viruses (SIVs) have an envelope (Env) glycoprotein with an unusually long cytoplasmic domain of 164 amino acids. In this article, we have characterized a series of SIV Env truncation mutants in which the cytoplasmic domain was progressively shortened from its carboxyl terminus by 20 amino acids. Expression by means of the vaccinia virus system showed that all of the SIV Env mutants were expressed and processed into the surface and transmembrane (TM) subunits. When the ability of the Env mutants to associate with SIV Gag particles was examined, we found that deletion of 20 to 80 residues from the carboxyl terminus of the SIV TM cytoplasmic tail abrogated the incorporation of the Env glycoprotein into particles. By contrast, further truncation of the SIV TM protein by 100 to 140 amino acids restored the ability of the Env protein to associate with Gag particles. Interestingly, mutants bearing a 44- or 24-amino acid cytoplasmic domain were incorporated at levels significantly higher than those of the wild-type Env. Single-cycle infectivity assays showed that Env mutants bearing cytoplasmic tails of 144 to 64 amino acids were highly inefficient at mediating virus entry. By contrast, truncation of the cytoplasmic domain to 44 or 24 amino acids drastically enhanced virus infectivity with respect to that conferred by the full-length Env protein. Our results demonstrate that small variations in the length of the SIV Env cytoplasmic domain dramatically influence Env-mediated viral functions.
AIDS Research and Human Retroviruses, 2012
We studied drug resistance mutations (DRMs) in 2623 pol sequences. Out of 94,828 amino acid subst... more We studied drug resistance mutations (DRMs) in 2623 pol sequences. Out of 94,828 amino acid substitutions that were detected, 8749 corresponded to nucleoside reverse transcriptase inhibitor (NRTI), 3765 to nonnucleoside reverse transcriptase inhibitor (NNRTI), and 7141 to protease inhibitor (PI) resistance-associated mutations. The most common DRMs were L10I, I54V, L90M, V82A, A71V, L10V, M46I, M184V, M41L, T215Y, D67N, L210W, K70R, N348I, V118I, K103N, Y181C, G190A, K101E, V108I, L100I, V90I, K101Q, and A98G. As expected, DRMs frequencies depended on viral genotype. The amounts of NRTI and PI resistance mutations among B and BF sequences from children were higher than among sequences from adults. The frequencies of PI and NRTI resistance mutations among B and BF sequences from adult men were higher than among sequences from women. Some of these observations can be explained in light of the available epidemiological information, but some cannot, indicating that further studies are needed to understand the antiretroviral resistance epidemics in Argentina.
AIDS Research and Human Retroviruses, 2009
The South American HIV-1 epidemic is characterized by the co-circulation of subtype B and BF reco... more The South American HIV-1 epidemic is characterized by the co-circulation of subtype B and BF recombinant variants. Together with the B and BF genotypes, HIV-1 subtype C (HIV-1C), F1, and several other recombinants have been reported. The epidemiological significance and immune correlates of these "non-B-non-BF" strains circulating in South America are still uncertain and therefore are increasingly attracting the interest of the scientific community. In this study, the South American HIV-1C epidemic was studied using new technologies for the phylogenetic analysis of large datasets. Our results indicate that there is a major clade encompassing most of the South American HIV-1C strains. These analyses also agreed that some strains do not group inside this major clade, suggesting that there could be HIV-1C sequences of different origins circulating in South America. Others have proposed different hypotheses about the origins of HIV-1C strains from South America. This study shows that an exact single origin cannot be determined, a fact that could be attributed to sampling problems, phylogenetic uncertainty, and the shortage of historical and epidemiological data. Currently, the reported data indicate that HIV-1C strains were introduced in Brazil and afterward spread to other regions of South America. By using character optimization on the obtained phylogenetic trees, we observed that Argentina could also be a point in which the HIV-1C epidemic entered South America.
Journal of Virology, 2003
Aids Research and Human Retroviruses, 2004
Papers by Julieta M Manrique
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Publications by Julieta M Manrique
Papers by Julieta M Manrique