[Antoni van leeuwenhoek — 300 years of oral microbiology]

Članak daje pregled Antoni van Leeuwenhoekovih pionirskih zapažanja o mikroorganizmima usne šupljine i osvrt na neke stavove u njegovom pismu upućenom Kraljevskom društvu u Londonu. U pismu od 17. rujna 1683. godine upućenom Kraljevskom društvu van Leeuwenhoek daje opise sadržaja dentalnog plaka koje je istraživao mikroskopom vlastite izrade. On opisuje spirohete nakon istraživanja dentalnog plaka starijeg čovjeka koji je izjavio da nikada nije prao svoje zube. Izgleda da je van Leeuwenhoek koristio promatranje bakterija u dentalnom plaku za motiviranje svojih posjetilaca na oralnu higijenu. Ta se metoda propagira i u suvremenoj terapiji parodonta. Značajan nastavak van Leeuwenhoekovih radova ilustrira briljantnost ideja prvog oralnog mikrobiologa.The article presents a review of Antoni van Leeuwenhoek’s pioneer observations of the oral microorganisms and his letter to the Royal Society in London. In the letter of September 17, 1683 to the Royal Society van Leeuwenhoek gives descriptions of the dental plaque specimens which he investigated with his self-made microscope. He describes a spirochete after the investigation of -dental plaque of an old man who declared never to have cleaned his teeth. Van Leeuwenhoek considered to use the observations of bacteria in dental plaque to motivate his visitors in oral hygiene. This method is recently propagated in periodontal practice. A remarkable continuation of van Leeuwenhoek\u27s works is an example of the brillant ideas of this first oral microbiologist

Brine Shrimp Toxicity Evaluation Of Some Tanzanian Plants Used Traditionally For The Treatment Of Fungal Infections

Plants which are used by traditional healers in Tanzania have been evaluated to obtain preliminary data of their toxicity using the brine shrimps test. The results indicate that 9 out of 44 plant species whose extracts were tested exhibited high toxicity with LC50 values below 20μg/ml. These include Aloe lateritia Engl. (Aloaceae) [19.1μg/ml], Cassia abbreviata Oliv. (Caesalpiniaceae) [12.7μg/ml], Croton scheffleri Pax (Euphorbiaceae) [13.7μg/ml], Hymenodactyon parvifolium Brig (Rubiaceae) [13.4μg/ml], Kigelia Africana L. (Bignoniaceae) [7.2μg/ml], and Ocimum suave Oliv. (Labiatae) [16.7μg/ml]. Twelve plants gave LC50 values between 21 and 50μg/ml, 11 plants gave LC50 values between 50 and 100 μg/ml, and 18 plants gave LC50 values greater than 100 μg/ml. Keywords: Brine shrimp test; Toxicity evaluation; Traditional antifungal plants African Journal of Traditional, Complementary and Alternative Medicines Vol. 4 (2) 2007: pp. 219-22

Species distribution and in vitro antifungal susceptibility of oral yeast isolates from Tanzanian HIV-infected patients with primary and recurrent oropharyngeal candidiasis

\ud In Tanzania, little is known on the species distribution and antifungal susceptibility profiles of yeast isolates from HIV-infected patients with primary and recurrent oropharyngeal candidiasis. A total of 296 clinical oral yeasts were isolated from 292 HIV-infected patients with oropharyngeal candidiasis at the Muhimbili National Hospital, Dar es Salaam, Tanzania. Identification of the yeasts was performed using standard phenotypic methods. Antifungal susceptibility to fluconazole, itraconazole, miconazole, clotrimazole, amphotericin B and nystatin was assessed using a broth microdilution format according to the guidelines of the Clinical and Laboratory Standard Institute (CLSI; M27-A2). Candida albicans was the most frequently isolated species from 250 (84.5%) patients followed by C. glabrata from 20 (6.8%) patients, and C. krusei from 10 (3.4%) patients. There was no observed significant difference in species distribution between patients with primary and recurrent oropharyngeal candidiasis, but isolates cultured from patients previously treated were significantly less susceptible to the azole compounds compared to those cultured from antifungal naïve patients. C. albicans was the most frequently isolated species from patients with oropharyngeal candidiasis. Oral yeast isolates from Tanzania had high level susceptibility to the antifungal agents tested. Recurrent oropharyngeal candidiasis and previous antifungal therapy significantly correlated with reduced susceptibility to azoles antifungal agents.\u

Sialic acid, periodontal pathogens and Tannerella forsythia: stick around and enjoy the feast!

Periodontal pathogens, like any other human commensal or pathogenic bacterium, must possess both the ability to acquire the necessary growth factors and the means to adhere to surfaces or reside and survive in their environmental niche. Recent evidence has suggested that sialic acid containing host molecules may provide both of these requirements in vivo for several periodontal pathogens but most notably for the red complex organism Tannerella forsythia. Several other periodontal pathogens also possess sialic acid scavenging enzymes – sialidases, which can also expose adhesive epitopes, but might also act as adhesins in their own right. In addition, recent experimental work coupled with the release of several genome sequences has revealed that periodontal bacteria have a range of sialic acid uptake and utilization systems while others may also use sialic acid as a cloaking device on their surface to mimic host and avoid immune recognition. This review will focus on these systems in a range of periodontal bacteria with a focus on Ta. forsythia

Proteolytic and oxidoreductase activity of Treponema denticola ATCC 35405 grown in an aerobic and anaerobic gaseous environment

The cells of a human oral spirochetes. Treponema denticola ATCC 35405, and of seven clinical isolates of this organism obtained from the subgingival dental plaque of periodontitis] patients were studied for their ability to grow in an aerobic and an anaerobic environment, and for their profile of peptidohydrolase and oxidoreductase enzymes. The growth yield of aerobically grown cultures was either comparable to or higher than that of anaerobically grown ones regardless of whether prereduced broth, freshly prepared broth or oxidized broth was used. However, elimination of certain supplements from the growth media resulted in poor growth regardless of the nature of the gaseous environment. The microscopic morphology and motility of the cells were not affected by differences in the gaseous atmosphere. Quantitative studies on several peptidohydrolase activities suggest that anaerobically grown cells displayed higher specific activity especially toward N[alpha]-L-prolyl-2-naphthylamine, indicating that increased synthesis of proline iminopeptidase enzymes (or enzyme) of the cells was associated with anaerobic growth conditions. The formation of enzymes hydrolysing N[alpha]-benzoyl-DL-arginyl-2-naphthylamine (and the corresponding p-nitroanilline) was not affected to the same extent. Growth experiments suggest that T. denticola ATCC 35405 is a facultatively anaerobic spirochete instead of an obligate anaerobe as reported in previous literature. The quantitative enzyme studies suggest that the gaseous growth atmosphere of the cells can exert a selective effect on the activity levels of certain peptidolytic enzymes of this organism. Such effects were not observed when the whole cells were studied by means of qualitative or semi-quantitative enzyme tests. The activities of catalase, peroxidase and superoxide dismutase of the cells were low and variable. Because of this, it was not possible to relate these oxidoreductase activities to the composition of the gaseous atmosphere.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31073/1/0000750.pd

De spirochetentest, een subgingivaleplak-verklikker

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Microscopic spirochete count in untreated subjects with and without periodontal tissue destruction

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