Karakterizacija i toksična aktivnost Aggregatibacter actinomycetemcomitans izolata

Periodontal diseases are widely distributed in the world and represent a major oral health problem both in developed and in developing countries. These chronic inflammatory diseases are characterized by the destruction of tooth supporting tissues. It is commonly accepted that dental plaque bacteria are the primary etiologic agents of periodontal disease. More than 700 species have been detected in the oral cavity in different individuals. Approximately 400 of these species have been isolated from different subgingival microenvironments. However, only a few species have been associated with the disease. From these bacteria specifically associated with destructive disease, Aggregatibacter actinomycetemcomitans is considered as one of the bacterial species of etiological importance in periodontitis and has contributed to the initiation and/or progression of destructive forms of periodontitis. The aim of this study was to evaluate the occurance characteristics and toxic activity of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Periodontal status of all included subjects was evaluated during the initial screening visit. A fullmouth clinical examination was performed in each patient using a manual probe and the following parameters were recorded at six sites per tooth: probing depth (PD in mm), clinical attachment loss (CAL in mm), bleeding on probing (BOP) and plaque index (PI). Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms and further molecular analysis. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using 16S rRNA gene sequencing. Genotyping was performed by polymerase chain reactions specific to the ltx promotor region, serotype-specific and cdt region and by sequencing of 16S rRNA. Cytotoxicity was examined on extravillous trophoblast cell line HTR-8/SVneo...Parodontalna oboljenja su široko rasprostanjena u celom svetu i u velikoj meri narušavaju oralno zdravlje, kako u razvijenim tako i u nerazvijenim zemljama. Parodontopatije su hronična inflamatorna oboljenja potpornog aparata zuba koja usled razaranja dubljih parodontalnih tkiva mogu da rezultiraju gubitkom zuba. Etiologija parodontopatije je polimikrobna po svojoj prirodi. Opisano više od 700 različitih vrsta mikroorganizama koje naseljavaju usnu duplju, od kojih je oko 400 izolovano iz subgingivalne regije. Međutim, samo nekoliko bakterijskih vrsta je dovedeno u vezu sa parodontopatijama, među kojima je i Aggregatibacter actinomycetemcomitans. Ovaj parodontopatogen se smatra veoma važnim u etiologiji parodontopatije, odnosno da doprinosi kako inicijaciji tako i progresiji destrukcije parodontalnih tkiva. Cilj ove studije je bio da se ispita prisustvo, karakteristike i toksična aktivnost bakterije A. actinomycetemcomitans poreklom iz subgingivalnog dentalnog plaka, kod obolelih od parodontopatije kao i kod osoba sa klinički zdravim parodoncijumom. Kod svih ispitanika uključenih u studiju, evidentiran je parodontalni status i nivo oralne higijene verifikacijom kliničkih parametara: dubinom sondiranja (DS u mm), nivoom pripojnog epitla (NPE u mm), krvarenjem na provokaciju (KNP) i plak indeksom (PI). Pulovani uzorci subgingivalnog dentalnog plaka su se koristili za kultivaciju i molekularne analize bakterije A. actinomycetemcomitans. Kultivacijom dobijene kolonije su selektovane u cilju identifikacije bakterije A. actinomycetemcomitans, sekvenciranjem 16S rRNK gena. Korišćene su specifične PCR reakcije u cilju genotipizacije promotorskog operona za leukotoksin, citoletalnog toksina istezanja i serotipizaciju kao i identifikaciju bakterije A. actinomycetemcomitans umnožavanjem dela gena za 16S rRNK. Ispitivan je uticaj bakterije A. actinomycetemcomitans na inhibiciju rasta ekstravilusne trofoblastne ćelijske linije HTR-8/SVneo..

Uitbeelding van apartheid in Engelse Suid-Afrikaanse jeugliteratuur

Summaries in Afrikaans and EnglishApartheid het die oorgrote meerderheid Suid-Afrikaners se lewens onherroeplik beinvloed. Dit is daarom te verstane dat dit in die Suid-Afrikaanse literatuur, insluitende die Engelse Suid-Afiikaanse jeugliteratuur, neerslag gevind het. Ten einde die studie in konteks te plaas, word in die eerste drie hoofstukke 'n historiese oorsig van die apartheidsera, Engelse Suid-Afrikaanse volwasse literatuur, en Engelse Suid-Afrikaanse kinderen jeugliteratuur, gegee. Die hoofgedeelte van die studie word vervolgens bespreek, en is in die volgende drie hoofstukke verdeel: • Die uitbeelding van sosio-ekonomiese toestande gedurende die apartheidsera, soos byvoorbeeld van afsonderlike woongebiede en aparte openbare geriewe. • Die uitbeelding van die onderwystoestande, veral van die Bantoe-onderwysbeleid. • Die uitbeelding van die veiligheidsmagte (polisie en weermag), insluitende die beeld van hierdie magte in die bree gemeenskap. Ten slotte word verskillende ooreenkomste wat na vore gekom bet in die bestudeerde Engelse Suid-Afrikaanse jeugromans waarin apartheid uitgebeeld word, bespreek. Daar word ook gekyk na die waarde van hierdie jeugromans.Apartheid had a irrevocably influence on the lives of the majority of people in South Africa. Therefore it is understandable that it would be portrayed in South African literature, including the English South African youth literature. To put the subject in context, the first three chapters ofthe thesis deal with a historical overview of the apartheidera; South African English adult literature; and South African English children's literature. The main part of the thesis has been divided as follows: • The portrayal of socio-economic conditions, e.g. separate residential areas and public amenities. • The portrayal of the education situation, especially the Black Education policy. • The portrayal of the security forces (police and army), including the images of these forces in the broader community. To conclude the thesis, similarities in the youth novels portraying apartheid are discussed. The value of these youth novels is also looked into.Information ScienceM. Inf

Characterisation and toxic activity of Aggregatibacter actinomycetemcomitans isolates

Parodontalna oboljenja su široko rasprostanjena u celom svetu i u velikoj meri narušavaju oralno zdravlje, kako u razvijenim tako i u nerazvijenim zemljama. Parodontopatije su hronična inflamatorna oboljenja potpornog aparata zuba koja usled razaranja dubljih parodontalnih tkiva mogu da rezultiraju gubitkom zuba. Etiologija parodontopatije je polimikrobna po svojoj prirodi. Opisano više od 700 različitih vrsta mikroorganizama koje naseljavaju usnu duplju, od kojih je oko 400 izolovano iz subgingivalne regije. Međutim, samo nekoliko bakterijskih vrsta je dovedeno u vezu sa parodontopatijama, među kojima je i Aggregatibacter actinomycetemcomitans. Ovaj parodontopatogen se smatra veoma važnim u etiologiji parodontopatije, odnosno da doprinosi kako inicijaciji tako i progresiji destrukcije parodontalnih tkiva. Cilj ove studije je bio da se ispita prisustvo, karakteristike i toksična aktivnost bakterije A. actinomycetemcomitans poreklom iz subgingivalnog dentalnog plaka, kod obolelih od parodontopatije kao i kod osoba sa klinički zdravim parodoncijumom. Kod svih ispitanika uključenih u studiju, evidentiran je parodontalni status i nivo oralne higijene verifikacijom kliničkih parametara: dubinom sondiranja (DS u mm), nivoom pripojnog epitla (NPE u mm), krvarenjem na provokaciju (KNP) i plak indeksom (PI). Pulovani uzorci subgingivalnog dentalnog plaka su se koristili za kultivaciju i molekularne analize bakterije A. actinomycetemcomitans. Kultivacijom dobijene kolonije su selektovane u cilju identifikacije bakterije A. actinomycetemcomitans, sekvenciranjem 16S rRNK gena. Korišćene su specifične PCR reakcije u cilju genotipizacije promotorskog operona za leukotoksin, citoletalnog toksina istezanja i serotipizaciju kao i identifikaciju bakterije A. actinomycetemcomitans umnožavanjem dela gena za 16S rRNK. Ispitivan je uticaj bakterije A. actinomycetemcomitans na inhibiciju rasta ekstravilusne trofoblastne ćelijske linije HTR-8/SVneo...Periodontal diseases are widely distributed in the world and represent a major oral health problem both in developed and in developing countries. These chronic inflammatory diseases are characterized by the destruction of tooth supporting tissues. It is commonly accepted that dental plaque bacteria are the primary etiologic agents of periodontal disease. More than 700 species have been detected in the oral cavity in different individuals. Approximately 400 of these species have been isolated from different subgingival microenvironments. However, only a few species have been associated with the disease. From these bacteria specifically associated with destructive disease, Aggregatibacter actinomycetemcomitans is considered as one of the bacterial species of etiological importance in periodontitis and has contributed to the initiation and/or progression of destructive forms of periodontitis. The aim of this study was to evaluate the occurance characteristics and toxic activity of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Periodontal status of all included subjects was evaluated during the initial screening visit. A fullmouth clinical examination was performed in each patient using a manual probe and the following parameters were recorded at six sites per tooth: probing depth (PD in mm), clinical attachment loss (CAL in mm), bleeding on probing (BOP) and plaque index (PI). Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms and further molecular analysis. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using 16S rRNA gene sequencing. Genotyping was performed by polymerase chain reactions specific to the ltx promotor region, serotype-specific and cdt region and by sequencing of 16S rRNA. Cytotoxicity was examined on extravillous trophoblast cell line HTR-8/SVneo..

Polymerase chain reaction in the identification of periodontopathogens: A reliable and satisfactory method?

Aggregatibacter actinomycetemcomitans is considered one of the bacterial species of etiological importance in periodontitis. The aim of this study was to evaluate the serotype of A. actinomycetemcomitans in the subgingival biofilm in subjects with periodontal health and disease. Pooled samples of subgingival plaque were taken for culture-based identification of microorganisms. Colonies suspected to be A. actinomycetemcomitans were selected for molecular identification using either multiplex or conventional PCR in serotype-specific genotyping and 16S rRNA gene sequencing. In silico analysis showed that most selected colonies belong to the genus Campylobacter, although positive signals for serotypes of A. actinomycetemcomitans were obtained with these samples. Identification of A. actinomycetemcomitans by conventional PCR for 16S rRNA with one species-specific and one universal primer was inconclusive because an almost identical signal with Campylobacter gracilis was obtained. Although PCR-based methods for the identification of A. actinomycetemcomitans are more rapid, sequencing should not be omitted. [Projekat Ministarstva nauke Republike Srbije, br. 41008 and br. 173048