Tritiated starch granules

1. Surface-labelling of starch granules by tritiation seems feasible, and a technique is described that could be useful in structure determination. The impurities that are produced must be taken into account but the fact that a high polymer can be successfully tritiated seems very promising. 2. The surfaces of corn-starch granules must contain both amylose and amylopectin.     

Die Variation bei den Statoblasten von Pectinatella magnifica

Ohne Zusammenfassung     

Avian paramyxoviruses from migrating and resident ducks in coastal Louisiana

Cloacal and tracheal swabs were collected from 1,409 hunter-killed ducks in Cameron Parish, Louisiana, during the 1986 and 1987 waterfowl seasons. Thirty avian paramyxoviruses (PMV's) were isolated from 605 blue-winged teal (Anas discors), 75 mottled ducks (A. fulvigula), 375 gadwalls (A. strepera), 334 green-winged teal (A. crecca), and 20 mallards (A. platyrhynchos). Prevalence of PMV decreased (P = 0.042) from September (4%) through November (2%) to December and January (1%). Juveniles had a higher prevalence of PMV (P less than 0.0001) than adults. An isolate from resident mottled ducks documents transmission of PMV's on the coastal wintering areas of Louisiana. The four serotypes isolated, PMV-1, PMV-4, PMV-6, and PMV-8, were typical of PMV's commonly associated with free-living waterfowl.     

Calcium, collagen dose, gender and fasting affect the response of rat platelet thromboxane formation to extremes in dietary linoleate

Platelet thromboxane synthesis in response to supplemental linoleate in the diet has been very inconsistent. The objective of this study was to investigate potential confounding factors known to affect platelet thromboxane synthesis. Citrated whole blood was recalcified with varying Ca2+ concentrations and challenged with low or high dose collagen preparations to induce extreme ranges of thromboxane synthesis from endogenous arachidonate pools by rat platelets. Male and female weanling rats were fed 0.0, 1.0 or 23 energy percent linoleate for 11 to 13 weeks. Fasting tended to enhance thromboxane synthesis. Both fasted and fed females showed slightly faster rates of thromboxane synthesis than males. Essential fatty acid deficiency depressed (P less than 0.01) thromboxane synthesis; the degree of this depression was inversely related to the level of recalcification (68% for 0.0 mM Ca2+, 36% for 2.5 mM Ca2+ and 20% for 5.0 mM Ca2+) when challenged with the high dose collagen. Essential fatty acid deficiency depressed platelet phospholipid arachidonate concentration 26%. Only blood from fed females stimulated with a mild challenge responded to excess dietary linoleate, and a 62% (not statistically significant) depression in TX synthesis was observed and this was associated with a decrease in platelet phospholipid arachidonate concentration.     

Metabolic modeling predicts specific gut bacteria as key determinants for Candida albicans colonization levels

Candida albicans is a leading cause of life-threatening hospital-acquired infections and can lead to Candidemia with sepsis-like symptoms and high mortality rates. We reconstructed a genome-scale C. albicans metabolic model to investigate bacterial-fungal metabolic interactions in the gut as determinants of fungal abundance. We optimized the predictive capacity of our model using wild type and mutant C. albicans growth data and used it for in silico metabolic interaction predictions. Our analysis of more than 900 paired fungal–bacterial metabolic models predicted key gut bacterial species modulating C. albicans colonization levels. Among the studied microbes, Alistipes putredinis was predicted to negatively affect C. albicans levels. We confirmed these findings by metagenomic sequencing of stool samples from 24 human subjects and by fungal growth experiments in bacterial spent media. Furthermore, our pairwise simulations guided us to specific metabolites with promoting or inhibitory effect to the fungus when exposed in defined media under carbon and nitrogen limitation. Our study demonstrates that in silico metabolic prediction can lead to the identification of gut microbiome features that can significantly affect potentially harmful levels of C. albicans.Subject terms: Fungi, Infectious diseases, Metagenomics, Gastrointestinal diseases, Microbiome