Analysis of the relationship between mannose-binding lectin (MBL) genotype, MBL levels and function in an Australian blood donor population.

The mannose-binding lectin (MBL) pathway of complement activation is an important component of innate host defence. Numerous studies have described associations between the MBL genotype, MBL levels and disease susceptibility. However, genotyping and quantitative assays used in these studies have frequently been limited, and comprehensive data examining the interaction between structural and coding MBL genetic variants, MBL antigenic levels and MBL functional activity are lacking. Such data may be important for accurate planning and interpretation of studies of MBL and disease. This study has examined MBL in a cohort of 236 Australian blood donors. Five MBL promoter and coding single nucleotide polymorphisms were genotyped using polymerase chain reaction-sequence-specific priming (PCR-SSP). Plasma levels of MBL antigen were quantified using a double-antibody enzyme-linked immunosorbent assay (ELISA), and functional MBL levels were quantified using a mannan-binding assay. Activation of the complement pathway by MBL was measured in a C4-deposition assay. Significant associations were found between both coding and promoter polymorphisms and MBL antigenic and functional levels. There was significant correlation between the results of MBL double-antibody, mannan-binding and C4-deposition assays. Comprehensive MBL genotyping and functional MBL quantitation using mannan-binding and C4-deposition assays have the potential to be highly informative in MBL disease association studies.

Biogenic production of cyanide and its application to gold recovery.

Chromobacterium violaceum is a cyanogenic (cyanide-producing) microorganism. Cyanide is used on an industrial scale to complex and recover gold from ores or concentrates of ores bearing the precious metal. A potentially useful approach in gold mining operations could be to produce cyanide biologically in relatively small quantities at the ore surface. In this study, C. violaceum grown in nutrient broth formed a biofilm and could complex and solubilize 100% of the gold on glass test slides within 4-7 days. Approximately 50% of the cyanide- recoverable gold could be mobilized from a biooxidized sulfidic-ore concentrate. Complexation of cyanide in solution by gold appeared to have a beneficial effect on cell growth--viable cell counts were nearly two orders of magnitude greater in the presence of gold-coated slides or biooxidized ore substrates than in their absence. C. violaceum was cyanogenic when grown in alternative feedstocks. When grown in a mineral salt solution supplemented with 13.3% v/v swine fecal material (SFM), cells exhibited pigmentation and suspended cell concentrations comparable to cultures grown in nutrient broth. Glycine supplements stimulated production of cyanide in 13.3% v/v SFM. In contrast, glycine was inhibitory when added at the time of inoculation in the more concentrated SFM, decreasing cell numbers and reducing ultimate bulk-solution cyanide concentrations. However, aeration and addition of glycine to stationary phase cells grown on 13.3% v/v SFM anaerobically resulted in rapid production and high concentrations (up to 38 mg l(-1)) of cyanide. This indicates that biogenesis of cyanide may be supported in remote areas using locally produced and inexpensive agricultural feedstocks in place of commercial media.

Frenkelia microti infection in a chinchilla (Chinchilla laniger) in the United States.

A Frenkelia microti tissue cyst was found in the brain of a chinchilla (Chinchilla laniger) used for biomedical research. This is the first report of Frenkelia infection in this animal in the United States.

Neural lesions in the rat and their relationship to EEG delta activity following seizures induced by the nerve agent soman.

This study describes the neural structures damaged following exposure to the nerve agent soman, shows there are time-dependent differences in the extent of damage in certain structures, and relates seizure-induced increases in delta band (0-3.5 Hz) electroencephalographic (EEG) activity with severity of subsequent neuropathology. Rats, instrumented to record cortical EEG activity, were pretreated with the oxime HI-6 (125 mg/kg, i.p.) and then challenged with soman (180 ug/kg, s.c.). All animals developed continuous epileptiform seizures that lasted in excess of 4 hr. Groups of animals were perfused 1, 3, 10 or 30 days following exposure. Paraffin-embedded brains were stained with hematoxylin and eosin; thirty-four neural structures were examined and scored for neural damage. All cortical areas sustained damage, with piriform and perirhinal cortices exhibiting the most severe. Subcortical limbic areas (amygdala, amygdala-piriform transition zone, hippocampus, claustrum) and various thalamic nuclei were most consistently and severely damaged in all animals regardless of survival time. Brainstem structures, cerebellum, spinal cord, and other motor output nuclei were never damaged. It was found that some structures were rated as more severely damaged when evaluated at shorter survival times. Severity of neural damage was related to high levels of EEG delta power recorded 24 hr after exposure; power during the acute seizure or 24 hr body weight loss did not predict lesion severity. Sections between AP -0.8 to -4.8 contain cortical and subcortical structures that can be readily and reproducibly evaluated for brain damage.

Guing of intense femtosecond pulses in preformed plasma channels.

We report guiding of sub-100-fs pulses at intensities up to 5x10(15) W/cm (2) over a distance of 1 cm in a preformed plasma channel. The width of the guided pulse was shortened, which we attribute to ionization-induced refraction at the channel entrance. A pulse energy throughput of 30% in the lowest-order was measured.

Coal Depyritization by the Thermophilic Archaeon Metallosphaera sedula.

The kinetics of pyrite oxidation by Metallosphaera sedula were investigated with mineral pyrite and two coals with moderate (Pittsburgh no. 8) and high (New Brunswick, Canada) pyritic sulfur content. M. sedula oxidized mineral pyrite at a greater rate than did another thermophile, Acidianus brierleyi, or a mesophile, Thiobacillus ferrooxidans. Maximum rates of coal depyritization were also greater with M. sedula, although the magnitude of biological stimulation above abiotic rates was notably less than with mineral pyrite. Coal depyritization appears to be limited by the oxidation of pyrite with ferric ions and not by the rate of biotic oxidation of ferrous iron, as evidenced by the maintenance of a high ratio of ferric to ferrous iron in solution by M. sedula. Significant precipitation of hydronium jarosite at elevated temperature occurred only with New Brunswick coal.