Browsing by Author "Rubio, J.M."
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Item A molecular marker for the identification of Simulium squamosum (Diptera: Simuliidae)(Annals of Tropical Medicine and Parasitology, 2004-03) Mank, R.; Wilson, M.D.; Rubio, J.M.; Post, R.J.All except one of the important groups of West African vectors of Onchocerca volvulus that lie within the Simulium damnosum complex can be distinguished from each other using morphological characteristics. The exception is S. squamosum, which overlaps with other species, and this results in significant levels of misidentification. Variation in the untranscribed H3-H4 histone intergenic spacer region of flies of the 5. damnosum complex has now been investigated. Although a CAA/CAG microsatellite was found to be hyper-variable and unsuitable for species diagnosis, a 10-bp indel seemed to vary in a species-specific manner. This indel was apparently absent from S. squamosum but present in all of the other species tested (S. damnosum s.s., S. sirbanum, S yahense, S. sanctipauli and 5. leonensel konkourense). It should now be possible to identify individual, adult, female S. squamosum from the absence of the indel, using a PCR-based amplification and agarose- or polyacrylamide-gel electrophoresis, thus removing the major barrier to the routine identification of unknown samples.Item Plasmodium falciparum immunodominant IgG epitopes in subclinical malaria(Scientific Reports, 2020-06-10) Fobil, J.N.; Azcárate, I.G.; Marín-García, P.; Abad, P.; Pérez-Benavente, S.; Paz-Artal, E.; Reche, P.A.; Rubio, J.M.; Diez, A.; Puyet, A.; Bautista, J.M.Incomplete non-sterile immunity to malaria is attained in endemic regions after recurrent infections by a large percentage of the adult population, who carry the malaria parasite asymptomatically. Although blood-stage Plasmodium falciparum rapidly elicits IgG responses, the target antigens of partially protective and non-protective IgG antibodies as well as the basis for the acquisition of these antibodies remain largely unknown. We performed IgG-immunomics to screen for P. falciparum antigens and to identify epitopes associated with exposure and clinical disease. Sera from malaria cases identified five prevalent antigens recognized by all analyzed patients’ IgGs. Epitope mapping of them, using adult and children sera samples from an endemic malaria region in Ghana segregated into patients with positive or negative subclinical detection of P. falciparum, revealed binding specificity for two 20-mer immunodominant antigenic regions within the START-related lipid transfer protein and the protein disulfide isomerase PDI8. These 20-mer epitopes challenged with sera samples from children under 5 years old displayed specific IgG binding in those with detectable parasitemia, even at subclinical level. These results suggest that humoral response against START and PDI8 antigens may be triggered at submicroscopic parasitemia levels in children and may eventually be used to differentially diagnose subclinical malaria in children.Item Polymorphisms in the human angiotensin converting enzyme gene (ACE) linked to susceptibility of COVID-19 and malaria infections in the Ghanaian population(Infection, Genetics and Evolution, 2024) Duah-Quashie, N.O.; Opoku-Agyeman, P.; Lanza, M.; Rubio, J.M.Genetic variations in the human angiotensin converting enzyme gene (ACE) influence ACE enzyme expression levels in humans and subsequently influence both communicable and non-communicable disease outcomes. More recently, polymorphisms in this gene have been linked to susceptibility and outcomes of infectious diseases such as the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and malaria infections. This study is the first to investigate the genetic diversity of ACE and ACE2 polymorphisms in the Ghanaian population. Archived filter blood blot samples from malaria patients aged ≤9 years were used. Molecular analysis for the detection of ACE rs4646994 (I/D), ACE2 rs2106809 (C/T) and rs2285666 (G/A) alleles as well as ACE2 exons 1–4 polymorphisms was conducted on 300 samples. The D allele (54%,162/300) was the most dominant polymorphism observed in the ACE rs4646994 gene whilst the G (68%, 204/300) and T alleles (59.3%,178/300) were the most frequent ACE2 rs2285666 and rs2106809 polymorphisms observed. For the 300 samples sequenced for ACE2 exons 1–4, analyses were done on 268, 282 and 137 quality sequences for exons 1, 2 and 3–4 respectively. For exon 1, the mutation D38N (2.2%; 6/268) was the most prevalent. The S19P and E37K mu tations previously reported to influence COVID-19 infections were observed at low frequencies (0.4%, 1/268 each). No mutations were observed in exon 2. The N121K/T variants were the most seen in exons 3–4 at fre quencies of 5.1% (K121, 7/137) and 2.9% (T121, 4/137) respectively. Most of the variants observed in the exons were novel compared to those reported in other populations in the world. This is the first study to investigate the genetic diversity of ACE and ACE2 genes in Ghanaians. The observation of novel mutations in the ACE2 gene is suggesting selection pressure. The importance of the mutations for communicable and non-communicable dis eases (malaria and COVID-19) are further discussed