Tyrosine phosphorylation of myosin heavy chain during skeletal muscle differentiation: an integrated bioinformatics approach

Previously it has been shown that insulin-mediated tyrosine phosphorylation of myosin heavy chain is concomitant with enhanced association of C-terminal SRC kinase during skeletal muscle differentiation. We sought to identify putative site(s) for this phosphorylation event. A combined bioinformatics approach of motif prediction and evolutionary and structural analyses identified tyrosines163 and 1856 of the skeletal muscle heavy chain as the leading candidate for the sites of insulin-mediated tyrosine phosphorylation. Our work is suggestive that tyrosine phosphorylation of myosin heavy chain, whether in skeletal muscle or in platelets, is a significant event that may initiate cytoskeletal reorganization of muscle cells and platelets. Our studies provide a good starting point for further functional analysis of MHC phosphor-signalling events within different cells.     

Antimalarial benzo[c]phenanthridines

Analogues of the antimalarial alkaloid nitidine have been prepared with high potency against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum in vitro. Simple modifications, using an established synthetic route, resulted in an analogue with IC(50) below 5ng/mL against a chloroquine-sensitive strain of P. falciparum. N-Ethylethoxidine had IC(50) below 30ng/mL against both chloroquine-sensitive and chloroquine-resistant strains of P. falciparum.     

Plasma glucose kinetics during prolonged exercise in trained humans when fed carbohydrate

Nine endurance-trained men exercised on a cycle ergometer at approximately 68% peak O2 uptake to the point of volitional fatigue [232 +/- 14 (SE) min] while ingesting an 8% carbohydrate solution to determine how high glucose disposal could increase under physiological conditions. Plasma glucose kinetics were measured using a primed, continuous infusion of [6,6-2H]glucose and the appearance of ingested glucose, assessed from [3-3H]glucose that had been added to the carbohydrate drink. Plasma glucose was increased (P < 0.05) after 30 min of exercise but thereafter remained at the preexercise level. Glucose appearance rate (R(a)) increased throughout exercise, reaching its peak value of 118 +/- 7 micromol. kg(-1). min(-1) at fatigue, whereas gut R(a) increased continuously during exercise, peaking at 105 +/- 10 micromol. kg(-1). min(-1) at the point of fatigue. In contrast, liver glucose output never rose above resting levels at any time during exercise. Glucose disposal (R(d)) increased throughout exercise, reaching a peak value of 118 +/- 7 micromol. kg(-1). min(-1) at fatigue. If we assume 95% oxidation of glucose R(d), estimated exogenous glucose oxidation at fatigue was 1.36 +/- 0.08 g/min. The results of this study demonstrate that glucose uptake increases continuously during prolonged, strenuous exercise when carbohydrate is ingested and does not appear to limit exercise performance.     

Genomics of phytopathogenic fungi and the development of bioinformatic resources

Genomic resources available to researchers studying phytopathogenic fungi are limited. Here, we briefly review the genomic and bioinformatic resources available and the current status of fungal genomics. We also describe a relational database containing sequences of expressed sequence tags (ESTs) from three phytopathogenic fungi, Blumeria graminis, Magnaporthe grisea, and Mycosphaerella graminicola, and the methods and underlying principles required for its construction. The database contains significant annotation for each EST sequence and is accessible at http://cogeme.ex.ac.uk. An easy-to-use interface allows the user to identify gene sequences by using simple text queries or homology searches. New querying functions and large sequence sets from a variety of phytopathogenic species will be incorporated in due course.     

Homocysteine and cysteine - albumin binding in homocystinuria: assessment of cysteine status and implications for glutathione synthesis?

Summary. Measurement of plasma total cysteine rather than free dimeric cystine gives a better indication of cysteine status in homocystinuric patients. This is the result of displacement of cysteine from albumin by homocysteine and is related to the plasma homocysteine concentration. In control subjects the free/bound cyst(e)ine ratio was independent of albumin and total cysteine concentrations. In homocystinuric (HCU) patients both free and total cyst(e)ine values differed significantly from control values (P < 0.001) but whilst free cystine considerably overlapped control values the total cysteine concentrations were almost invariably lower. The possible consequences of this on glutathione synthesis was explored by assay of plasma total glutathione but no evidence for glutathione deficiency was found. Measurement of total cysteine, rather than free cystine, provides a better indication of cysteine status in HCU. Received February 1, 2001 Accepted November 13, 2001     

Rainforest habitat resistance to the migration of Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) in south-eastern Queensland

Abstract  This paper tests the hypothesis that habitat differences affect the migratory ability of the Chilean predatory mite, Phytoseiulus persimilis , an introduced biological control agent of the spider mite, Tetranychus urticae . It is suggested that habitat resistance accounts for the species' inability to invade rainforests in south-eastern Queensland, Australia. Like its prey, P. persimilis migrates to distant plants on air currents. To test our hypothesis, populations of the Chilean predatory mite were established on potted bean plants in both remnant rainforest and adjacent open fields, and their migration monitored using sticky traps. Overall it was found that prey populations on leaves were similar in both habitats, but those of predators were about 20% lower in rainforest. However, the numbers of both predators and prey caught on sticky traps in rainforest were about 6% and 25%, respectively, of those caught in open fields, indicating a strongly reduced rate of aerial migration in the forest. The number of P. persimilis caught on the sticky traps increased with increasing populations of predators on foliage. Thus, dense vegetation inhibits the movement of air currents and inhibits colonisation by both predators and, to a lesser extent, spider mites. These results suggest that the inhibition of aerial migration is one reason for lower numbers of P. persimilis in forest habitats, both because its own vagility is restricted, and because its prey is less able to disperse.     

Development of a culturally sensitive food frequency questionnaire for use in the Southern Community Cohort Study.

A food frequency questionnaire (FFQ) was developed to assess long-term habitual dietary intake in a cohort of approximately 100,000 40 to 79 year-old men and women living in the Southeastern US. Using the NHANES-III database for the southem region for specific race and sex subgroups, a list of 262 food categories was developed, coded and reduced to 102 food items that could discriminate between racial groups and account for large portions of cancer-relevant nutrients. The developed FFQ was tested in a pilot study in three southeastern states involving 239 African Americans and Whites, aged 56.9 +/- 12.2 years. The frequencies of consumption and portion sizes of the 102 foods were determined and intakes of various nutrients were estimated and compared with the NHANES-III data. African Americans reported higher total energy intakes and higher consumption of macronutrients and several micronutrients, compared to Whites. Estimated nutrient indices were higher among pilot study than among NHANES-III participants, although adjustment for total energy essentially eliminated the differences. Analysis of the frequency distribution of individual foods shows that the questionnaire includes commonly eaten foods that can discriminate between African Americans and Whites. The FFQ is currently being calibrated within the cohort study population.