Maria Helena Ramirez Hernandez

Maria Helena Ramirez Hernandez
National University of Colombia | UNAL · Departamento de Biología (Bogotá)

PhD

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31
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Publications

Publications (31)
Article
Los sistemas de defensa anti-oxidante utilizados por el parásito intracelular Leishmania braziliensis durante el proceso de infección permiten eliminar especies reactivas de oxígeno y nitrógeno a expensas de equivalentes reductores derivados de la tripanotiona, evitando daños celulares del patógeno. Con el objetivo de identificar potenciales blanco...
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La nicotinamida/nicotinato mononucleótido adenililtransferasa (NMNAT, EC 2.7.7.1/18) desempeñauna función central en la síntesis del dinucleótido de adenina y nicotinamida (NAD) debido a queen esta enzima confluyen las rutas de síntesis de novo y de reciclaje. El NAD es una moléculatrascendental en el metabolismo de todos los seres vivos, principal...
Article
The intracellular parasite Leishmania braziliensis is the etiological agent of cutaneous leishmaniasis, an endemic disease in the tropics, whose pharmacological treatments are toxic and for which there is currently no vaccine. For this reason, the study of proteins related to the energy metabolism of the parasite is relevant given its importance fo...
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Nicotinamide adenine dinucleotide (NAD) is one of the central molecules involved in energy homeostasis, cellular signaling and antioxidative defense systems. Consequently, its biosynthetic pathways and transport systems are of vital importance. The nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT), a key enzyme in the biosynthesis...
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Nicotinamide adenine dinucleotide (NAD) is an essential coenzyme involved in REDOX reactions and oxidative stress defense systems. Furthermore, NAD is used as substrate by proteins that regulate essential cellular functions as DNA repair, genetic, and signal transduction, among many others. NAD biosynthesis can be completed through the de novo and...
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Nicotinamide adenine dinucleotide phosphate (NADP) is an essential biomolecule that participates in the redox homeostasis and synthesis of signaling compounds. NAD kinase (NADK) (EC 2.7.1.23 / 2.7.1.86) is the only enzyme capable of synthesizing NADP. This study offers an approach to the NADP metabolism in the parasite Giardia intestinalis, the eti...
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The sirtuins are a group of well-conserved proteins widely distributed across all domains of life. These proteins are clustered in the class III of histone deacetylases and are distinctly characterized by their dependence upon NAD ⁺ to carry out the deacetylation of lysine residues in histone proteins (H3 and H4) and non-histones such as the transc...
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BACKGROUND Nicotinamide adenine dinucleotide (NAD) plays a central role in energy metabolism and integrates cellular metabolism with signalling and gene expression. NAD biosynthesis depends on the enzyme nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT; EC: 2.7.7.1/18), in which converge the de novo and salvage pathways. OBJECTIVE...
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Full-text available
Nicotinamide adenine dinucleotide phosphate (NADP) is an essential biomolecule that participates in the redox homeostasis and synthesis of signaling compounds. NAD kinase (NADK) (EC 2.7.1.23 / 2.7.1.86) is the only enzyme capable of synthesizing NADP. This study offers an approach to the NADP metabolism in the parasite Giardia intestinalis, the eti...
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Full-text available
The biochemical pathways involved in nicotinamide adenine dinucleotide (NAD) biosynthesis converge at the enzymatic step catalysed by nicotinamide mononucleotide adenylyltransferase (NMNAT, EC: 2.7.7.1). The majority of NMNATs are assembled into homo-oligomeric states that comprise 2-6 subunits. Recently, the NMNAT of Plasmodium falciparum (PfNMNAT...
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Background: Nicotinamide adenine dinucleotide (NAD+) is an essential molecule in the energy metabolism of living beings, and it has various cellular functions. The main enzyme in the biosynthesis of this nucleotide is nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1/18) because it is the convergence point for all known...
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Recombinant proteins have become useful tools in biochemistry research. During their production, however, inclusion bodies (IB) appear, on the one hand, due to the high expression rate from the recombinant plasmids, which have high efficiency promoters, and. on the other hand, intrinsic characteristics of the expressed protein. Furhtermore, the nic...
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Full-text available
Nicotinamide mononucleotide adenylyl transferase (NMNAT) is a key enzyme in the biosynthesis of nicotinamide adenine dinucleotide (NAD+), which is an essential molecule in cellular metabolism. Specific sequences have been described in other NMNATs, which are associated with the regulation of catalytic activity and intracellular localization. In add...
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Full-text available
Nicotinamide/nicotinate adenine dinucleotide (NAD+/NaAD) performs essential functions in cell metabolism and energy production due to its redox properties. The nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT, EC 2.7.7.1/18) enzyme catalyses the key step in the biosynthesis of NAD+. Previously, the enzyme NMNAT was identified in Tr...
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The intracellular parasite Trypanosoma cruzi is the aetiological agent of Chagas disease, a public health concern with an increasing incidence rate. This increase is due, among other reasons, to the parasite’s drug resistance mechanisms, which require nicotinamide adenine dinucleotide (NAD+). Furthermore, this molecule is involved in metabolic and...
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Giardia lamblia is an intestinal protozoan parasite that causes giardiasis, a disease of high prevalence in Latin America, Asia and Africa. Giardiasis leads to poor absorption of nutrients, severe electrolyte loss and growth retardation. In addition to its clinical importance, this parasite is of special biological interest due to its basal evoluti...
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The progressive increase in Leishmania resistance to current control approaches prompts the need to develop therapeutic strategies based on comprehensive knowledge of the parasite's biology. The enzyme Nicotinamide Mononucleotide Adenylyltransferase (NMNAT, EC 2.7.7.1) catalyzes the central step in nicotinamide adenine dinucleotide (NAD(+)) biosynt...
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In contrast with other animal models, the use of hens for polyclonal antibodies production not only reduces animal intervention, but also increases the quantity of the obtained immunoglobulins. The phylogenetic distance between birds and mammals, leads to more specific avian antibodies than their mammalian counterparts. Since a large amount of anti...
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Leishmania braziliensis is a protozoan which is cause of the most of the cutaneous leishmaniasis cases in at least 15 countries from America. World Health Organization (WHO) has reported that around 12 millions of people are infected in the world and this number increase every year. Because of the delicate problem of public health due to the preval...
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Leishmania braziliensis es un parásitoprotozoario causante de la mayor partede casos de leishmaniasis cutánea enal menos quince países del continenteamericano. La Organización Mundial dela Salud (OMS) ha reportado que cercade doce millones de personas están infectadasen el mundo y que este númeroaumenta cada año. Debido al delicadoproblema de salud...
Article
Since the beginning of the last century, seminal discoveries have identified pyridine nucleotides as the major redox carriers in all organisms. Recent research has unravelled an unexpectedly wide array of signalling pathways that involve nicotinamide adenine dinucleotide (NAD) and its phosphorylated form, NADP. NAD serves as substrate for protein m...
Article
Fanconi anemia (FA) is a hereditary disease of unknown pathogenic mechanisms, although mutations in seven different genes can be causative. Six of these genes have been cloned and sequenced. Only slight homology to the DNA of any other known gene has been found with the exception of FANCG which is identical to XRCC9. The function of these genes, in...
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The cause of the molecular defect of Fanconi anemia (FA) remains unknown. Cells from patients with FA exert an elevated spontaneous chromosomal instability which is further triggered by mitomycin C. The induced lability is reduced by overexpression of thioredoxin which is not the case for spontaneous instability. However, both are eliminated by ove...
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Fanconi anemia (FA) is an autosomal recessive chromosomal breakage disorder characterized by developmental defects, hypersensitivity toward oxygen and DNA crosslinking agents, and susceptibility to cancer. An increased level of reactive oxygen intermediates and an increased level of 8-oxoguanine in FA cells point to a defective oxygen metabolism. R...
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Full-text available
Fanconi anemia (FA) is an autosomal recessive disorder characterized by skeletal abnormalities, pancytopenia and a marked predisposition to cancer. FA cells exhibit chromosomal instability and hypersensitivity towards oxygen and cross-linking agents such as diepoxybutane and mitomycin C. An increased level of reactive oxygen intermediates and an el...

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Projects (2)
Archived project
Estudiar el metabolismo del NAD en parásitos protozoos, en busca de proteínas específicas que puedan constituir nuevos blancos quimioterapéuticos, mediante la identificación de posibles transportadores de NAD y la exploración de los mecanismos de regulación génica asociados a esta ruta