Fungal diversity in the gut microbiome of young South African children.

BACKGROUND: The fungal microbiome, or mycobiome, is a poorly described component of the gut ecosystem and little is known about its structure and development in children. In South Africa, there have been no culture-independent evaluations of the child gut mycobiota. This study aimed to characterise the gut mycobiota and explore the relationships between fungi and bacteria in the gut microbiome of children from Cape Town communities. METHODS: Stool samples were collected from children enrolled in the TB-CHAMP clinical trial. Internal transcribed spacer 1 (ITS1) gene sequencing was performed on a total of 115 stool samples using the Illumina MiSeq platform. Differences in fungal diversity and composition in relation to demographic, clinical, and environmental factors were investigated, and correlations between fungi and previously described bacterial populations in the same samples were described. RESULTS: Taxa from the genera Candida and Saccharomyces were detected in all participants. Differential abundance analysis showed that Candida spp. were significantly more abundant in children younger than 2 years compared to older children. The gut mycobiota was less diverse than the bacterial microbiota of the same participants, consistent with the findings of other human microbiome studies. The variation in richness and evenness of fungi was substantial, even between individuals of the same age. There was significant association between vitamin A supplementation and higher fungal alpha diversity (p = 0.047), and girls were shown to have lower fungal alpha diversity (p = 0.003). Co-occurrence between several bacterial taxa and Candida albicans was observed. CONCLUSIONS: The dominant fungal taxa in our study population were similar to those reported in other paediatric studies; however, it remains difficult to identify the true core gut mycobiota due to the challenges set by the low abundance of gut fungi and the lack of true gut colonising species. The connection between the microbiota, vitamin A supplementation, and growth and immunity warrants exploration, especially in populations at risk for micronutrient deficiencies. While we were able to provide insight into the gut mycobiota of young South African children, further functional studies are necessary to explain the role of the mycobiota and the correlations between bacteria and fungi in human health.

Classification of chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride and glucosamine 6 sulfate using chemometric techniques.

Chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride and glucosamine sulfate are natural products that are becoming increasingly popular in the treatment of arthritis. They belong to a class of compounds known as glycosaminoglycans (GAGs). They are available over the counter as nutritional supplements. However, increasing use has led to increasing scrutiny of the quality of products on the market. There is also interest in the pharmacological properties of these compounds. To facilitate this, there is a need for better qualitative and quantitative methods of analysis. This paper describes methods for achieving the qualitative identification of chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride or glucosamine sulfate. Fourier transform infrared spectroscopy coupled with a variety of chemometric methods successfully classified these compounds. Using soft independent modeling of class analogies (SIMCA), hierarchical cluster analysis (HCA) and principal components analysis (PCA) samples were classified as either chondroitin sulfate A, chondroitin sulfate C, glucosamine hydrochloride or glucosamine sulfate. This work also examined the discriminating ability of different sections of the spectrum. It was found that for the classification of these compounds that using the finger print region of the spectrum (below 2000 cm(-1)) gave the best discrimination.

Comparison of equations describing band broadening in high-performance liquid chromatography.

Several models are well established that describe band broadening in gas and liquid chromatography, including those due to Van Deemter and Knox. Comparison of competing models is complicated if raw data are noisy or if the equations to be fitted to data contain many adjustable parameters. This paper describes a comparison of fitting the Van Deemter, Knox and other equations to low noise data gathered during the separation of propyl- and methylparaben by HPLC. Equations are compared using established statistical methods, including analysis of residuals, inference of parameter estimates and Akaikes Information Criterion for model identification. This work indicates that equations that account for non-linear band broadening at elevated mobile phase velocities are more successful at describing the relationship between height equivalent to a theoretical plate, H, and the velocity of the mobile phase, u.

Fear-potentiated startle: relationship to the level of state/trait anxiety in healthy subjects.

The startle reflex is potentiated during experimentally induced anxiety (fear-potentiated startle). It is also increased in various anxiety disorders. The present study investigated the relationship between individual differences in fear and anxiety, and startle modulation. The eyeblink component of the acoustic startle reflex was measured in a paradigm involving the anticipation of electric shocks in 22 healthy men who were volunteers. Each subject's fear of shock was assessed with the state portion of the State-Trait Anxiety Inventory (STAI; Spielberger 1983). Fear-potentiated startle, but not baseline startle, differed in the low and high fear subjects. The magnitude of fear-potentiated startle was larger in the high-fear group as compared to the low-fear group. The time-course of startle modulation suggested a longer duration of anticipatory anxiety in the high-fear group. Trait anxiety, which was assessed with the trait portion of the STAI, did not relate to individual differences in either baseline or fear-potentiated startle.

An open study of the safety and efficacy of enoxacin in complicated urinary tract infections.

Thirty-one patients with serious or complicated urinary tract infections were treated with oral enoxacin for between four and eight days. Twenty-five patients with microbiologically confirmed infections completed treatment with 400 mg enoxacin twice daily and at the end of treatment all urine cultures were negative. At short term follow-up, five to nine days after therapy, 21 of the 25 patients were still infection free. In total, reinfection or relapse occurred in 12 patients during the four to six weeks follow up period after termination of treatment. Significant side-effects (nausea and vomiting) occurred in only one patient.

The effect of growth temperature on the membrane lipid environment of the psychrophilic bacterium Micrococcus cryophilus.

The relationship between the delta 9-desaturase activity of the psychrophilic bacterium Micrococcus cryophilus grown at different temperatures and the physical state of its membrane lipids as measured by ESR spectroscopy has been studied. Arrhenius plots of desaturase activity were biphasic with a discontinuity at a temperature which depended upon the bacterial growth temperature. Changes in the desaturase activation energy, which increased as the growth temperature was lowered, are discussed in the context of membrane lipid fluidity adaptation to changing environmental temperature. The fluidity of membranes and isolated lipids was measured using nitroxide-labeled fatty acids. The spectra of 2-(10-carboxydecyl)-2-hexyl-4,4-dimethyl-3-oxazolidinoxyl in membranes indicated that there were two lipid environments within the membrane whose relative proportions were dependent both on temperature of measurement and on bacterial growth temperature. In contrast, 2-(3-carboxypropyl)-4,4-dimethyl-2-tridecyl-3-oxazolidinoxyl spectra showed a single lipid environment and plots of log order parameter (S3) vs 1/T were biphasic with inflexion temperatures which were closely related to the bacterial growth temperature. As with membranes, plots of log S3 vs 1/T for total lipids, phosphatidylglycerol and cardiolipin, but not phosphatidylethanolamine, were biphasic and showed inflexions which correlated well with bacterial growth temperature. These results are interpreted as being consistent with a location for the desaturase within the bulk lipid of the membrane rather than in association with specific lipid types.

Effect of dietary lipid on synaptosomal acetylcholinesterase activity.

The effect of dietary lipid on the thermotropic properties of acetylcholinesterase activity was examined in rat synaptosomal membrane preparations after feeding diets containing soya-bean oil, sunflower oil or soya-bean phosphatidylcholine as the dietary fats. Arrhenius plots and energies of activation were altered by the duration of feeding as a function of time, as well as by the composition of diet fat fed. Animals fed sunflower oil had the highest maximal velocity for acetylcholinesterase activity. The observations of this study suggest that dietary fat is an important determinant of the physicokinetic properties of lipid-dependent functions in brain synaptosomal membranes.

Some properties, including the substrate in vivo, of the delta 9-desaturase in Micrococcus cryophilus.

The delta 9-desaturase of the psychrophilic bacterium Micrococcus cryophilus is shown to be a membrane-bound enzyme that is probably linked to a cyanide- (and azide-) sensitive respiratory chain with oxygen as the final acceptor. It has a pH optimum of 8.7 and contains an essential thiol group, but has no special ion requirements. The desaturase activity of washed membranes could not be increased by adding supernatant or NADH and NADPH, possibly owing to the endogenous generation of reduced cofactors by the membranes. The substrate for the desaturase is not acyl-CoA and is probably not acyl-acyl-carrier protein. Evidence is presented that the substrate in vivo is saturated phospholipid and a scheme for the possible routes of incorporation of exogenous stearic acid into oleoyl-phospholipid is presented.

Plasma membrane: can its structure and function be modulated by dietary fat?

Compositional analysis of plasma membranes from rats fed nutritionally adequate diets different in fatty acid composition establishes that fundamentally different dietary fat intake results in alteration in structural lipid composition of plasma membranes in brain, liver and the intestinal mucosa. Dietary differences in fatty acid intake altered the fatty acyl tail composition of plasma membrane phospholipids in brain, liver and intestinal mucosa. Diet altered the phospholipid profile observed in brain synaptosomal and liver plasma membrane. Feeding high vs low polyunsaturated to saturated fat diets for 7 days altered the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and monoglucosylceramide isolated from plasma membrane of the intestinal mucosa.

Influence of dietary fat on the lipid composition of rat brain synaptosomal and microsomal membranes.

The modulation of rat brain microsomal and synaptosomal membrane lipid by diet fat was examined. Brain synaptosomal and microsomal membrane composition was compared for rats fed on diets containing either soya-bean oil (SBO), SBO plus choline, SBO lecithin, sunflower oil (SFO), chow or low-erucic acid rape-seed oil (LER) for 24 days. Cholesterol and phosphatidylcholine levels in both membranes were altered by diet. Diet fat also affected the microsomal content of sphingomyelin. Change in membrane phosphatidylcholine level was related to the relative balance of omega-6, omega-3 and monounsaturated fatty acids within the diets fed. The highest phosphatidylcholine levels appeared in membranes of animals fed on SBO lecithin and the lowest in those fed on LER. Microsomal membrane cholesterol and sphingomyelin content increased by feeding on SBO lecithin. In both synaptosomal and microsomal membranes a highly significant correlation was observed between membrane phosphatidylcholine and cholesterol content. The fatty acyl composition of phospholipids from both membranes also altered with diet and age. Alteration in fatty acid composition was observed in response to dietary levels of omega-6, omega-3 and monounsaturated fatty acids, but the unsaturation index of each phospholipid remained constant for all diet treatments. These changes in lipid composition suggest that dietary fat may be a significant modulator in vivo of the physicobiochemical properties of brain synaptosomal and microsomal membranes.