Journal Article•
Inhibition of Leishmania major PTR1 Gene Expression by Antisense in Escherichia coli.
30 Jun 2012-Iranian Journal of Public Health (Tehran University of Medical Sciences)-Vol. 41, Iss: 6, pp 65-71
TL;DR: In inhibition of Iranian L. coli strain M15, major PTR1 expression with mRNA antisense in prokaryotic system as an approach to appear of the drugs therapeutic effects more.
Abstract: Background: Protozoa related to Trypanosome family including Leishmania , synthesize enzymes to escape from drug therapy. One of them is PTR1 that its enzymatic activity is similar to dihydrofolate reductase (DHFR). Dihydrofolate reductase - thymidylate synthase has a major role in DNA synthesis, if it is inhibited, the result would be the death of parasite. Since PTR1 activity is similar to DHFR, causes the decrease of inhibition effect of drug. The aim of this study was inhibition of Iranian L. major PTR1 expression with mRNA antisense in prokaryotic system as an approach to appear of the drugs therapeutic effects more. Methods: PTR1 gene was ligated to pACYCDuet-1 and pcDNA3 plasmids as sense and antisense plasmids, respectively. Simultaneously transfer of sense and antisense plasmids was done in E. coli strain M15. SDS-PAGE and western blot analysis were carried out to analyze the expression. Results: Sense and antisense plasmids were prepared and confirmed by restriction analysis and PCR then simultaneously transfer of them was done. SDS-PAGE and western blot analysis showed PTR1 gene was inhibited by mRNA antisense in bacterial cells. Conclusion: Expression of PTR1 gene in sense plasmid was inhibited successfully by antisense plasmid.
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TL;DR: In this article, the authors evaluated the antileishmanial, antioxidant, and cytotoxic activities of Quercus infectoria Olivier (oak) extract and found that oak significantly inhibited the growth rate of promastigote and amastigotes.
61 citations
TL;DR: This review focuses on recent findings in drugs used for the treatment of leishmaniasis including; chemical and natural antileishmanial moieties, different potential targets, as well as various trials of vaccination development.
55 citations
TL;DR: Through molecular docking it was found that two sesquiterpene coumarins are promising leads for the P TR1 and TryS inhibition purposes, and some xanthanolides also exhibited better affinity towards PTR1 and CS binding.
Abstract: A great number of sesquiterpenes are reported in the available literature as good antileishmanial leads. However, their mode of action at the molecular level has not been elucidated. The lack of molecular studies could be considered an impediment for studies seeking to improve sesquiterpene-based drug design. The present in silico study allows us to make important observations about the molecular details of the binding modes of a set of antileishmanial sesquiterpenes against four drug-enzyme targets [pteridine reductase-1 (PTR1), N-myristoyl transferase (NMT), cysteine synthase (CS), trypanothione synthetase (TryS)]. Through molecular docking it was found that two sesquiterpene coumarins are promising leads for the PTR1 and TryS inhibition purposes, and some xanthanolides also exhibited better affinity towards PTR1 and CS binding. In addition, the affinity values were clustered by Principal Component Analysis and drug-like properties were analyzed for the strongest-docking sesquiterpenes. The results are an excellent starting point for future studies of structural optimization of this kind of compounds.
27 citations
TL;DR: It could be concluded that both sequence and size of antisense oligonucleotide were important for transfection of L. major and hybridized gold nanoparticles not only could silence GP63 gene, but also could kill L.major.
16 citations
TL;DR: Adherence to vaccination is fairly common in this part of the country, however, vaccination delays are still present and should be addressed to improve health care.
Abstract: Objectives: To assess vaccination timeliness, risk factors associated with delays and the reasons for delayed vaccinations among children below the age of 3 years in Jeddah, Kingdom of Saudi Arabia. Methods: This is a cross-sectional study conducted in Jeddah, Saudi Arabia during the period of May 2016 to August 2017. Data were obtained from parents of children under the age of 3 years using a structured questionnaire comprised of questions about sociodemographics, physical well-being of the child and the reasons that are used to justify delayed vaccinations. Vaccinations were considered delayed if they occurred more than 30 days after the time designated on the primary vaccination schedule. Logistic regression was used to assess the risk factors for vaccination delays. Results: The study included 351 children. Delayed vaccinations were observed in 85/351 (24.2%) of the sample. Delays were noted to occur most frequently for Measles, Mumps, Rubella vaccine (MMR), seconddose of meningococcal conjugate quadrivalent vaccine (MCV4), second dose of oral polio vaccine (OPV) and fourth dose of pneumococcal conjugate vaccine (PCV) in 19/125 (15.2%) of the sample. Traveling at the time of vaccination was the most common delay reason and was reported in 31/142 (21.3%) of the sample. Conclusion: Adherence to vaccination is fairly common in this part of the country. However, vaccination delays are still present and should be addressed to improve health care. Saudi Med J 2018; Vol. 39 (4): 347-353 doi: 10.15537/smj.2018.4.21473 How to cite this article: Banjari MA, Alamri AA, Algarni AY, Abualjadayel MH, Alshardi YS, Alahmadi TS. How often do children receive their vaccinations late, and why? Saudi Med J . 2018 Apr;39(4):347-353. doi: 10.15537/smj.2018.4.21473.
14 citations
References
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TL;DR: The basic mechanisms of parasite resistance in malaria, sleeping sickness, leishmaniasis and common helminthiases are reviewed.
Abstract: Drug resistance is complicating the treatment of parasitic diseases. We review here the basic mechanisms of parasite resistance in malaria, sleeping sickness, leishmaniasis and common helminthiases. Parasites resort to multiple biochemical means to achieve resistance and we have begun to isolate and characterize the genes/proteins implicated in resistance. Understanding drug resistance is essential for the control of parasitic diseases.
80 citations
"Inhibition of Leishmania major PTR1..." refers background in this paper
...In addition to reports in the world about Leishmania which is resistant to drugs (19, 20) in Iran 10 to 15 percent of people infected with cutaneous leishmaniasis have been treated with Glucantime; they have no response to treatment that one of the reasons is drug-resistant parasites (21)....
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TL;DR: It is shown that these resistant parasites are cross-resistant to the other SbV-containing drug Pentostam and at least for one isolate also to amphotericin B, and the latter two drugs could thus be useful alternatives for the treatment of leishmaniasis in Iran even for S bV-resistant isolates.
Abstract: Cutaneous leishmaniasis (CL) is a major health problem in endemic areas of Iran. The pentavalent antimony (SbV) based drug Glucantime is the first line of treatment for CL in Iran, but recently SbV-resistant Leishmania tropica isolates derived from unresponsive patients were reported. We show in this study that these resistant parasites are cross-resistant to the other SbV-containing drug Pentostam and at least for one isolate also to amphotericin B. However, these resistant isolates were shown to be sensitive to miltefosine and paromomycin. The latter two drugs could thus be useful alternatives for the treatment of leishmaniasis in Iran even for SbV-resistant isolates.
79 citations
"Inhibition of Leishmania major PTR1..." refers background in this paper
...In addition to reports in the world about Leishmania which is resistant to drugs (19, 20) in Iran 10 to 15 percent of people infected with cutaneous leishmaniasis have been treated with Glucantime; they have no response to treatment that one of the reasons is drug-resistant parasites (21)....
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TL;DR: A new class of noncoding RNAs ranging from ∼300 to 600 nucleotides in size that are expressed specifically in the intracellular amastigote stage that is the first report describing developmentally regulated ncRNAs in protozoan parasites.
Abstract: Leishmania is a protozoan parasite that causes serious morbidity and mortality in humans worldwide. The ability of these parasites to survive within the phagolysosomes of mammalian macrophages is dependent on the developmental regulation of a variety of genes. Identifying genomic sequences that are preferentially expressed during the parasite's intracellular growth would provide new insights about the mechanisms controlling stage-specific gene regulation for intracellular development of the parasite. Using a genomic library that differentially hybridized to probes made from total RNA from Leishmania infantum amastigote or promastigote life cycle stages, we identified a new class of noncoding RNAs (ncRNAs) ranging from approximately 300 to 600 nucleotides in size that are expressed specifically in the intracellular amastigote stage. These ncRNAs are transcribed by RNA polymerase II from genomic clusters of tandem head-to-tail repeats, which are mainly located within subtelomeric regions. Remarkably, both the sense and antisense orientations of these ncRNAs are transcribed and are processed by trans splicing and polyadenylation. The levels of antisense transcripts are at least 10-fold lower than those of the sense transcripts and are tightly regulated. The sense and antisense ncRNAs are cytosolic as shown by fluorescence in situ hybridization studies and cosediment with a small ribonucleoprotein complex. Amastigote-specific regulation of these ncRNAs possibly occurs at the level of RNA stability. Interestingly, overexpression of these ncRNAs in promastigotes, as part of an episomal expression vector, failed to produce any transcript, which further highlights the instability of these RNAs in the promastigote stage. This is the first report describing developmentally regulated ncRNAs in protozoan parasites.
49 citations
"Inhibition of Leishmania major PTR1..." refers result in this paper
...In addition, it was shown that the inhibition occurs in the cytosol, as was reported by Dumas et al (31)....
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TL;DR: Transfection of L. major with the mutant DHFR-TS gene gives parasites that are capable of growing in medium containing 10 mM methotrexate, showing that the altered DHFR gene is in itself capable of conferring MTX resistance in Leishmania.
42 citations
TL;DR: The study shows that Ldccys2 is a developmentally regulated gene and that Leishmania (L.) chagasi is expressed only in infectious amastigote stages of the parasite, and antisense RNA inhibition is used as an alternate approach to gene knockout for silencing gene expression.
Abstract: The parasitic protozoa belonging to Leishmania (L.) donovani complex possess abundant, developmentally regulated cathepsin L-like cysteine proteases. Previously, we have reported the isolation of cysteine protease gene, Ldccys2 from Leishmania (L.) chagasi. Here, we have further characterized this cysteine protease gene and demonstrated its role during infection and survival of Leishmania (L.) chagasi within the U937 macrophage cells. The amastigote specific Ldccys2 genes of L. (L.) chagasi and L. (L.) donovani have identical gene organization, as determined by southern blots. In vivo expression analyses by Northern blots showed that Ldccys2 is amastigote specific. Western blot using anti-Ldccys2 antibody confirmed the amastigote specific protein expression. Recombinant expression of Ldccys2, a 30 kDA protein, was functionally active in a gelatin assay. Results from Ldccys2 heterozygous knockout mutants showed its role during macrophage infection and in intra-macrophage survival of the parasites. Since attempts to generate null mutants failed, we used antisense RNA inhibition to regulate Ldcccys2 gene expression. Not surprisingly, the results from antisense studies further confirmed the results from heterozygous knockout mutants, reiterating the importance of amastigote specific cysteine proteases in Leishmania infection and pathogenesis. The study shows that Ldccys2 is a developmentally regulated gene and that Ldccys2 is expressed only in infectious amastigote stages of the parasite. The collective results from both the heterozygous knockout mutants and antisense mRNA inhibition studies shows that Ldccys2 helps in infection and survival of L. (L.) chagasi amastigotes within the macrophage cells. Finally, antisense RNA technique can be used as an alternate approach to gene knockout, for silencing gene expression in L. (L.) chagasi, especially in cases such as this, where a null mutant cannot be achieved by homologous recombination.
38 citations
"Inhibition of Leishmania major PTR1..." refers background in this paper
...To inhibit gene expression, different several ways have been reported such as, oligodeoxy nucleotides (ODNs) (28), mRNA antisense (29) and small interfering RNA (siRNA) molecules (30)....
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