Terminalia ferdinandiana Exell. Extracts inhibit the growth of body odour-forming bacteria.

OBJECTIVE: Terminalia ferdinandiana extracts are potent growth inhibitors of many bacterial pathogens. They may also inhibit the growth of malodour-producing bacteria and thus be useful deodorant components, although this is yet to be tested. METHODS: Terminalia ferdinandiana fruit and leaf solvent extracts were investigated by disc diffusion and liquid dilution MIC assays against the most significant bacterial contributors to axillary and plantar malodour formation. Toxicity was determined using the Artemia franciscana nauplii bioassay. Non-targeted HPLC separation of the methanolic leaf extract coupled to high-resolution time-of-flight (TOF) mass spectroscopy was used for the identification and characterization of individual components in the extract. RESULTS: The T. ferdinandiana leaf extracts were the most potent bacterial growth inhibitors. The leaf methanolic extract was particularly potent, with low MIC values against C. jeikeium (233 µg mL-1 ), S. epidermidis (220 µg mL-1 ), P. acnes (625 µg mL-1 ) and B. linens (523 µg mL-1 ). The aqueous and ethyl acetate leaf extracts were also potent growth inhibitors of C. jeikeium and S. epidermidis (MICs < 1000 µg mL-1 ). In comparison, the fruit extracts were substantially less potent antibacterial agents, although still with MIC values indicative of moderate growth inhibitory activity. All T. ferdinandiana leaf extracts were non-toxic in the Artemia franciscana bioassay. Non-biased phytochemical analysis of the methanolic leaf extract revealed the presence of high levels of and high diversity of tannins and high levels of the flavone luteolin. CONCLUSION: The low toxicity of the T. ferdinandiana leaf extracts and their potent growth inhibition of axillary and plantar malodour-producing bacteria indicate their potential as deodorant components.

Interactions regulating the head-to-tail directed assembly of biological Janus rods.

The directed, head-to-tail self-assembly of microtubule filaments may be generalized in the context of Janus colloidal rods. Specifically, their assembly at the tens of micron-length scale involves a careful balance between long-range electrostatic repulsion and short-range attractive forces. Here we show that the addition of counterion salts increases the rate of directed assembly by screening the electrostatic forces and enhancing the effectiveness of short-range interactions at the microtubule ends.

Cross-cultural differences in the management of children and adolescents with diabetes.

Glycaemic control deteriorates frequently in adolescents with diabetes. There is a considerable body of work on the effect of psychological aspects of management in this age group, but few randomized controlled trials of the effect of specific behavioural therapy and lifestyle modification on the improvement of glycaemic control. Of recent interest have been the observations from the Hvidøre Study Group on cross-cultural differences in glycaemic control. The average glycosylated haemoglobin in 22 centres, across 18 countries, varied in young people, with HbA1c levels ranging from 7.6 to 10.2%. No obvious differences in management were identified in this survey that could account for the disparities in glycaemic control. Data from the Scottish Study Group demonstrated similar variation in average glycaemic control in centres across a single culture. Using the qualitative methodology of anthropological research, some specific factors were identified that appear to influence young people's response to diabetes management and strategies employed by health professionals in their advice and care of the diabetes, particularly in relation to intensive insulin regimens. The main cultural factors influencing glycaemic control appear to be communication, reciprocal support between young people and professional heart carers and family structure within an individualistic, as against an egalitarian, society. Shared beliefs about teenage risk behaviour together with the medicalization of adolescence within medical culture also appears to be highly influential. The aim of this educational discussion group was to explore how a variety of health care professionals from distinctive cultures approach diabetes care delivery in this age group. The specific success and difficulties in different cultures in managing the young person with diabetes were investigated. Also discussed was how qualitative research methodology may generate further research in this area.

Deferribacter thermophilus gen. nov., sp. nov., a novel thermophilic manganese- and iron-reducing bacterium isolated from a petroleum reservoir.

A thermophilic anaerobic bacterium, designated strain BMAT (T = type strain), was isolated from the production water of Beatrice oil field in the North Sea (United Kingdom). The cells were straight to bent rods (1 to 5 by 0.3 to 0.5 microns) which stained gram negative. Strain BMAT obtained energy from the reduction of manganese (IV), iron(III), and nitrate in the presence of yeast extract, peptone, Casamino Acids, tryptone, hydrogen, malate, acetate, citrate, pyruvate, lactate, succinate, and valerate. The isolate grew optimally at 60 degrees C (temperature range for growth, 50 to 65 degrees C) and in the presence of 2% (wt/vol) NaCl (NaCl range for growth, 0 to 5% [wt/vol]). The DNA base composition was 34 mol% G + C. Phylogenetic analyses of the 16S rRNA gene indicated that strain BMAT is a member of the domain Bacteria. The closest known bacterium is the moderate thermophile Flexistipes sinusarabici (similarity value, 88%). Strain BMAT possesses phenotypic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, we propose that this isolate should be described as a member of a novel species of a new genus, Deferribacter thermophilus gen. nov., sp. nov.

Microbial formation of manganese oxides.

Microbial manganese oxidation was demonstrated at high Mn concentrations (5 g/liter) in bacterial cultures in the presence of a microalga. The structure of the oxide produced varied depending on the bacterial strain and mode of culture. A nonaxenic, acid-tolerant microalga, a Chlamydomonas sp., was found to mediate formation of manganite (gamma-MnOOH). Bacteria isolated from associations with crude cultures of this alga grown in aerated bioreactors formed disordered gamma-MnO(2) from Mn at concentrations of 5 g/liter over 1 month, yielding 3.3 g of a semipure oxide per liter. All algal-bacterial cultures removed Mn from solution, but only those with the highest removal rates formed an insoluble oxide. While the alga was an essential component of the reaction, a Pseudomonas sp. was found to be primarily responsible for the formation of a manganese precipitate. Medium components-algal biomass and urea-showed optima at 5.7 and 10 g/liters, respectively. The scaled-up culture (50 times) gave a yield of 22.3 g (53 mg/liter/day from a 15-liter culture) of semipure disordered gamma-MnO(2), identified by X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy, and had a manganese oxide O/Mn ratio of 1.92. The Mn(IV) content in the oxide was low (30.5%) compared with that of mined or chemically formed gamma-MnO(2) (ca. 50%). The shortfall in the bacterial oxide manganese content was due to biological and inorganic contaminants. FTIR spectroscopy, transmission electron microscopy, and electron diffraction studies have identified manganite as a likely intermediate product in the formation of disordered gamma-MnO(2).

Mutagenicity of dimethyl heteroaromatic triazenes in the Ames test: the role of hydrophobicity and electronic effects.

The mutagenicities of five heterocyclic 3,3-dimethyltriazenes have been evaluated in the Ames test. The octanol-water partition coefficients (P) for these triazenes have been measured, and their electron distributions and molecular orbital energies were calculated using the MNDO semiempirical molecular orbital method. Molecular structures of three triazenes have been determined using X-ray crystallography. The mutagenicities of these five triazenes, which range from nearly inactive to very highly mutagenic, are well predicted by quantitative structure-activity relationships that had been derived previously for the mutagenicity of aryltriazenes. The form of these equations indicates that more hydrophobic and more electron-rich triazenes are more active in the Ames test. This supports the hypothesis that the ease of initial triazene activation by cytochrome P-450 governs the mutagenicity of these compounds.

Effect of oral disopyramide therapy on left ventricular function.

To study the effect of oral disopyramide therapy on left ventricular function, a subject of some controversy, we obtained first-pass radionuclide ventriculograms with a multicrystal gamma camera in 19 patients with or without therapy. Our findings demonstrated that disopyramide causes deterioration in left ventricular function in patients with abnormal ejection fractions. This effect is rarely recognized clinically and occurs despite safe therapeutic serum levels.