Browsing by Subject "Chlamydia pneumoniae"

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  • Heiskari, Mikko (Helsingfors universitet, 2011)
    Based on earlier studies, it was known that certain 2,1,3-benzoxadiazole molecules were active against Chlamydia pneumoniae -bacterium. The goal of this study was to gather more information about structure-activity relationships of the 2,1,3-benzoxadiazole molecules. The purpose of a research was to develop a synthesis route for 2,1,3-benzoxadiazole molecules and build a molecular library based on the results. Synthesized molecules were tested against Chlamydia pneumoniae -bacterium and Leishmania donovani -parasites. Chlamydia pneumoniae -bacterium causes acute upper and lower respiratory tract infections such as bronchitis. The symptoms of acute inflammation of the Chlamydia pneumoniae can vary considerably. Chlamydia pneumoniae can also cause chronic infections. Chronic infections are linked to economically important diseases such as atherosclerosis and asthma. Leishmaniosis is the second most common parasitic disease in humans after malaria. Leishmania donovani -parasite can cause fatal visceral leishmaniasis. Leishmaniasis kills more than 50 000 people each year. In recent years, medical treatment for leishmaniasis has encountered many problems. Some of the medicines have lost their efficiency and some of them cause serious side effects. Fully functional synthesis route was developed for a 2,1,3-benzoxadiazole derivatives. 4-Amino-2-nitro benzoic acid was used as a starting material. With a oxidative ring-closure reaction 2,1,3-benzoxadiazole-5-carboxyl acid was obtained. 2,1,3-benzoxadiazole-5-carbonitrile was synthesized from the corresponding carboxyl acid via amide intermediate. When 2,1,3-benzoxadiazole-5-carbonitrile was treated with hydroxylamine hydrochloride, carboximidamide was obtained, which was a common intermediate for all the final products. At the final stage N'-hydroxy-2,1,3-benzoxadiazole-5-carboximidamide was let to react with either phenyl isocyanate or phenyl isothiocyanate to give the final products. Development of a synthesis route proved to be challenging so at the end three final products were synthesized. One of the final products was tested against C. pneumoniae -bacterium in the Åbo Akademi, Turku. The test compound did not contain 2,1,3-benzoxadiazole ring structure and the result was in line with expectations. The compound was not active against C. pneumoniae at low concentrations and the results showed that 2,1,3-benzoxadiazole ring is an important part of the activity. Two of the final products were tested against Leishmania donovani parasite in Israel. Only one of the molecules contained 2,1,3-benzoxadiazole ring. The results of the bioactivity test were very encouraging. Compounds were active against the parasite at low concentrations. However, the 2,1,3-benzoxadiazole compound was more active. Also the result of Leishmania test shows that 2,1,3-benzoxadiazole ring structure was found to be an important part of the activity.
  • Reijonen, Visa-Aleksi (Helsingin yliopisto, 2020)
    Making the treatment of these infections even harder is the fact, that Chlamydia pneumoniae can produce persistent forms of itself, which are immune to antibiotic treatment. When the bacteria sense a stress factor, for example the presence of a β-lactam antibiotic or interferon γ, they start producing these persistent forms called aberrant bodies. When the stress factor is removed, the bacteria can switch back to their replicating form and start infecting the tissues again. It is also known, that C. pneumoniae bacteria will trigger persistence when the bacteria migrate from lung epithelia into monocytes. Interestingly the onset of this mode of persistence does not require any other triggers besides the invasion of the monocyte. These persistence mechanisms enable latent, quiet, and recurring infections. This master’s thesis aimed to study the coculture of lung epithelial (HL cells) and monocytes (THP-1 cells), and by utilising the magnetic separation method presented by Kortesoja et al, to find a positive control compound in the prevention of Chlamydia pneumoniae internalisation into the THP-1 cells for said protocol. In these cocultures the inhibitory effect of different compound groups such as lignans present in Schisandra chinensis plant, MAPK-inhibitors, and β2,2-amino acid derivatives in C. pneumoniae migration from HL cells to THP-1 cells was assessed. Statistic relevance was observed in JNK inhibitor SP600125, MAPKAP-kinase-2 inhibitor SB203580, and ERK1/2 inhibitor FR180204 compounds. These compounds inhibited the internalisation of Chlamydia pneumoniae into THP-1 cells in the cell coculture by 61,05 ± 16,63 % (p = 0,0001), 54,06 ± 16,02 % (p = 0,0002), and 36,76 ± 10,33 % (p = 0,009) respectively. SP600125 and SB 203580 compounds also had an inhibitory effect on the internalisation of C. pneumoniae into the THP-1 cells in a cell monoculture (39,98 ± 18,92 %, p = 0,026 and 37,89 ± 19,47 %, p = 0,035 respectively), whereas FR180204 had no statistical significance, even though it inhibited the internalisation of C. pneumoniae into the THP-1 cells in cell monoculture by 27,53 ± 21,17 %. From the compounds used in the experiments, only MAPK inhibitors had an effect in inhibiting the C. pneumoniae internalisation into the THP-1 cells. The most potent compound in said inhibition was the JNK inhibitor SP600125. JNK pathway has been thought to take part in chlamydial infections but only little research has been done. The results of this master’s thesis’ experiments support the thought of JNK enzyme taking part in chlamydial infections but determining how exactly it affects the infection cycle of C. pneumoniae bacteria still needs further investigation.
  • Linnanmäki, Eila (University of Helsinki, 1996)
  • Kaukoranta-Tolvanen, Suvi-Sirkku (University of Helsinki, 1994)
  • Penttilä, Tuula (University of Helsinki, 1995)
  • Nummi, Maaret; Mannonen, Laura; Puolakkainen, Mirja (2015)
    The aim of this study was to improve detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in clinical specimens by developing a multiplex real-time PCR assay that includes identification of macrolide-resistant M. pneumoniae. Novel assays targeting a M. pneumoniae conserved hypothetical protein gene, M. pneumoniae 23S rRNA gene mutations associated with macrolide resistance and human beta-globin gene (an endogenous internal control) were designed and combined with a previously published C. pneumoniae PCR targeting ompA gene. The resulting quadraplex PCR was validated with a panel of clinical specimens supplemented with external quality assessment specimens, simulated specimens and various bacterial and viral strains. The obtained results were compared to those obtained by reference PCRs or confirmed by sequencing (typing of macrolide resistance). The novel multiplex PCR assay was in 100 % agreement with reference PCRs. Four M. pneumoniae strains with macrolide resistance-associated mutations were identified among 42 strains, which comprises 9.5 % of the study material. Amplification of an internal control excluded sample-derived inhibition possibly leading to false-negative reporting. In conclusion, we have developed a resources conserving multiplex real-time PCR assay for simultaneous detection of M. pneumoniae, C. pneumoniae and the most common mutations leading to macrolide resistance in M. pneumoniae. The assay is a widely useful tool for detection of these respiratory pathogens and will also shed light on the occurrence of macrolide resistance in M. pneumoniae.
  • Hokynar, Kati; Kurkela, Satu; Nieminen, Tea; Saxen, Harri; Vesterinen, Eero J.; Mannonen, Laura; Pietikäinen, Risto; Puolakkainen, Mirja (2019)
    Community-acquired pneumonia (CAP) is a common disease responsible for significant morbidity and mortality. However, the definite etiology of CAP often remains unresolved, suggesting that unknown agents of pneumonia remain to be identified. The recently discovered members of the order Chlamydiales, Chlamydia-related bacteria (CRB), are considered as possible emerging agents of CAP. Parachlamydia acanthamoebae is the most studied candidate. It survives and replicates inside free-living amoeba, which it might potentially use as a vehicle to infect animals and humans. A Mycoplasma pneumoniae outbreak was observed in Kymenlaakso region in Southeastern Finland during August 2017-January 2018. We determined the occurrence of Chlamydiales bacteria and their natural host, free-living amoeba in respiratory specimens collected during this outbreak with molecular methods. Altogether, 22/278 (7.9%) of the samples contained Chlamydiales DNA. By sequence analysis, majority of the CRBs detected were members of the Parachlamydiaceae family. Amoebal DNA was not detected within the sample material. Our study further proposes that Parachlamydiaceae could be a potential agent causing atypical CAP in children and adolescents.