Cell surface properties of Pseudomonas stutzeri in the process of diesel oil biodegradation

Pseudomonas stutzeri, isolated from crude oil-contaminated soil, was used to degrade diesel oil. Of three surfactants, 120 mg rhamnolipids 1−1 significantly increased degradation of diesel oil giving 88% loss after 14 days compared to 54% loss without the surfactant. The system with rhamnolipids was characterised by relatively high particle homogeneity. However, the addition of saponins to diesel oil caused the cells to aggregate (the polydispersity index: 0.542) and the biodegradation of diesel oil was only 46%. The cell yield was 0.22 g l−1

Knowledge and Attitude of clinical level dental students concerning HIV/AIDS

Objective: To determine the knowledge and attitude of clinical level dental students concerning Human Immunodeficiency Virus/Acquired Immune Deficiency Syndrome (HIV/AIDS). Methods: Two hundred and fifteen clinical level dental students from three Nigerian universities were requested to complete a self- administered questionnaire related to knowledge and attitudes about HIV/AIDS. Parameters assessed included the aetiology and modes of transmission, high- risk groups, common oral and general manifestations, diagnosis, treatment and prevention of HIV/AIDS. Results: The male to female ratio was approximately 1:1, with an age range of 20-36 years. The respondents exhibited excellent knowledge of the aetiologic agent, the modes of transmission, high- risk groups, common oral manifestations and prevention of HIV/AIDS. However, they were less knowledgeable about the general features, diagnosis, treatment, aims of treatment and infection control measures. One hundred and sixty (70.4%) of the respondents stated that they did not have any reservations dealing with patients with HIV/AIDS while 55 (29.6%) felt that with improved knowledge they would be more confident in issues related to HIV/AIDS. Conclusion: Although Nigerian dental students exhibited good knowledge and positive attitude concerning HIV/AIDS, this study showed that knowledge of laboratory investigations and infection control measures were poor. These areas need emphasis in the dental school curriculum. Keywords: Knowledge, attitude, dental student, HIV/AIDSNigerian Dental Journal Vol. 15 (1) 2007: pp. 3-

Selective isolation of bacteria from soil with hydrophobic materials

Bacterial strains having a hydrophobic cell surface have often been considered as degraders of hydrophobic organic pollutants in soil. In this study, bacterial strains were isolated using hydrophobic materials from 12 soil samples, and their cell surface hydrophobicity was determined by evaluating their adherence to n-hexane. Bacterial strains isolated using polytetrafluoroethylene (PTFE) membrane were more hydrophobic on an average than those isolated with styrene-divinylbenzene (DVB) particles or octadecylsilyl silica gel (ODS) particles. Strains closely related to Burkholderia cepacia could be selectively isolated using the PTFE membrane; those closely related to Ralstonia pickettii, using ODS and DVB particles; and those closely related to B. fungorum, using DVB. These results indicate that bacterial strains having a hydrophobic cell surface or within certain phyla can be selectively isolated from soils using hydrophobic materials, and that this isolation method would be useful for collecting candidates for bioremediation of hydrophobic pollutants