Phylogeny of Greya (Lepidoptera: Prodoxidae), based on nucleotide sequence variation in mitochondrial cytochrome oxidase I and II: congruence with morphological data

The phylogeny of Greya Busck (Lepidoptera: Prodoxidae) was inferred from nucleotide sequence variation across a 765-bp region in the cytochrome oxidase I and II genes of the mitochondrial genome. Most parsimonious relationships of 25 haplotypes from 16 Greya species and two outgroup genera (Tetragma and Prodoxus) showed substantial congruence with the species relationships indicated by morphological variation. Differences between mitochondrial and morphological trees were found primarily in the positions of two species, G. variabilis and G. pectinifera, and in the branching order of the three major species groups in the genus. Conflicts between the data sets were examined by comparing levels of homoplasy in characters supporting alternative hypotheses. The phylogeny of Greya species suggests that host-plant association at the family level and larval feeding mode are conservative characters. Transition/transversion ratios estimated by reconstruction of nucleotide substitutions on the phylogeny had a range of 2.0-9.3, when different subsets of the phylogeny were used. The decline of this ratio with the increase in maximum sequence divergence among taxa indicates that transitions are masked by transversions along deeper internodes or long branches of the phylogeny. Among transitions, substitutions of A-->G and T-->C outnumbered their reciprocal substitutions by 2-6 times, presumably because of the approximately 4:1 (77%) A+T-bias in nucleotide base composition. Of all transversions, 73%-80% were A<-->T substitutions, 85% of which occurred at third positions of codons; these estimates did not decrease with an increase in maximum sequence divergence of taxa included in the analysis. The high frequency of A<-->T substitutions is either a reflection or an explanation of the 92% A+T bias at third codon positions.      

Arginine synthesis is regulated by dietary arginine intake in the enterally fed neonatal piglet

Arginine is conditionally indispensable in the neonate, and its synthesis in the intestine is not sufficient to meet requirements. It is not known how neonatal endogenous arginine synthesis is regulated and the degree to which proline and glutamate are used as precursors. Primed, constant intraportal and intragastric infusions of L-[U-14C]proline and L-[3,4-3H]glutamate, and intragastric L-[guanido-14C]arginine were used to measure whole body and first-pass intestinal arginine synthesis in 10 neonatal piglets fed generous (1.80 g.kg(-1).day(-1)) or deficient (0.20 g.kg(-1).day(-1)) quantities of arginine for 5 days. Glutamate tracer was not detected in arginine, indicating a biologically insignificant conversion of <1% of arginine flux. Endogenous arginine synthesis from proline had obligatory (0.36 g.kg(-1).day(-1)) and maximal (0.68 g.kg(-1).day(-1)) levels (P < 0.05, pooled SE 0.05). Although first-pass gut metabolism is responsible for 42-63% of whole body arginine synthesis, the gut is incapable of upregulating proline to arginine conversion during arginine deficiency, compared with a more than threefold increase without first-pass gut metabolism. These data suggest that upregulation of proline-to-arginine conversion occurs via increased arterial extraction of proline by the gut or in nonintestinal tissues. This study demonstrates that dietary arginine is an important regulator of endogenous arginine synthesis in the neonatal piglet and that proline, but not glutamate, is an important precursor for arginine synthesis in the neonate.     

A critical appraisal of clinical practice guidelines for the treatment of lower-limb osteoarthritis

Clinical practice guidelines are important tools to assist clinical decision-making. Recently, several guidelines addressing the management of osteoarthritis (OA) have been published. Clinicians treating patients with OA must ensure that these guidelines are developed with consistency and methodological rigour. We undertook a qualitative summary and critical appraisal of six medical treatment guidelines for the management of lower-limb OA published in the medical literature within the past 5 years. A review of these six guidelines revealed that each possesses strengths and weakness. While most described the scope and intended patient populations, the guidelines varied considerably in the rigour of their development, coverage of implementation issues, and disclosure of conflicts of interest.     

Analysis of plastid DNA-like sequences within the nuclear genomes of higher plants

A wide-ranging examination of plastid (pt)DNA sequence homologies within higher plant nuclear genomes (promiscuous DNA) was undertaken. Digestion with methylation-sensitive restriction enzymes and Southern analysis was used to distinguish plastid and nuclear DNA in order to assess the extent of variability of promiscuous sequences within and between plant species. Some species, such as Gossypium hirsutum (cotton), Nicotiana tabacum (tobacco), and Chenopodium quinoa, showed homogenity of these sequences, while intraspecific sequence variation was observed among different cultivars of Pisum sativum (pea), Hordeum vulgare (barley), and Triticum aestivum (wheat). Hypervariability of plastid sequence homologies was identified in the nuclear genomes of Spinacea oleracea (spinach) and Beta vulgaris (beet), in which individual plants were shown to possess a unique spectrum of nuclear sequences with ptDNA homology. This hypervariability apparently extended to somatic variation in B. vulgaris. No sequences with ptDNA homology were identified by this method in the nuclear genome of Arabidopsis thaliana.      

A critical appraisal of clinical practice guidelines for the treatment of lower-limb osteoarthritis

Clinical practice guidelines are important tools to assist clinical decision-making. Recently, several guidelines addressing the management of osteoarthritis (OA) have been published. Clinicians treating patients with OA must ensure that these guidelines are developed with consistency and methodological rigour. We undertook a qualitative summary and critical appraisal of six medical treatment guidelines for the management of lower-limb OA published in the medical literature within the past 5 years. A review of these six guidelines revealed that each possesses strengths and weakness. While most described the scope and intended patient populations, the guidelines varied considerably in the rigour of their development, coverage of implementation issues, and disclosure of conflicts of interest.     

Measurement of homocysteine and related metabolites in human plasma and urine by liquid chromatography electrospray tandem mass spectrometry

The sulfur amino acids, methionine and cysteine play crucial roles in cells as a substrate for protein synthesis, as a methyl donor, and for the synthesis of sulfur-containing compounds, including the key intracellular tripeptide, glutathione. Homocysteine is an intermediary metabolite formed during the metabolism of methionine to cysteine. Dysregulation of homocysteine metabolism is implicated in adverse clinical outcomes such as increased risk of cardiovascular disease, stroke, Alzheimer's disease dementia and osteoporosis. While hyperhomocysteinemia is commonly observed in those conditions, the impact on other related metabolites is condition-specific. Therefore, there exists a need to establish precise and sensitive analytical techniques that allow for the simultaneous measurement of homocysteine and related metabolites in biological samples. The current review outlines the development and use of liquid chromatography electrospray tandem mass spectrometry (LC–MS/MS) to simultaneously measure metabolites involved in sulfur amino acid metabolism. Additionally, extensions of the technique in relation to the measurement of sulfur amino acid and one-carbon kinetics in vivo are discussed. The LC–MS/MS technique has the capacity for unambiguous analyte identification and confirmation, due to its high specificity and sensitivity. It has the greatest potential of being accepted and utilized as a dedicated homocysteine and its related metabolite Standard reference method (SRM).     

Modulation of human erythrocyte shape and fatty acids by diet

A semi-synthetic diet (Vivonex) was administered via nasogastric tube to three cystic fibrosis patients with pancreatic exocrine deficiency for 14 days to gain weight. Dietary essential fatty acids were provided as safflower oil, which constituted 1.3% of total calories. Plasma and red blood cells were analyzed for the content and composition of lipids at the start of the diet and at days 7 and 14 of the dietary period, and the results were correlated with the morphology of the cells. Feeding Vivonex to the patients led to an essential fatty acid deficiency, which was manifested in a 50% decrease in the linoleic acid content of the phosphatidylcholine of plasma and red blood cells at days 7 and 14 and in a 20% decrease in the linoleic acid content of red cell phosphatidylethanolamine at day 14. There was no significant alteration in the levels or composition of the other phospholipid classes and in the free cholesterol/phospholipid ratio. The decrease in the linoleic acid content of the erythrocytes was accompanied by a dramatic increase in the proportion of cells as echinocytes. We conclude that restricted linoleic acid availability in cystic fibrosis patients causes a change in red blood cell shape either directly by decreasing the linoleoylphosphatidylcholine content of the membrane or indirectly by affecting enzyme activity.     

Phenylalanine requirement in children with classical PKU determined by indicator amino acid oxidation

Dietary restriction of phenylalanine is the main treatment for phenylketonuria (PKU), and current estimates of requirements are based on plasma phenylalanine concentration and growth. The present study aimed to determine more precisely the phenylalanine requirements in patients with the disease by use of indicator amino acid oxidation, with L-[1-13C]lysine as the indicator. Breath 13CO2 production (F 13 CO2) was used as the end point. Finger-prick blood samples were also collected for measurement of phenylalanine to relate phenylalanine intake to blood phenylalanine levels. The mean phenylalanine requirement, estimated using a two-phase linear regression crossover analysis, was 14 mg. kg(-1). day(-1), and the safe population intake (upper 95% confidence interval of the mean) was found to be 19.5 mg. kg(-1). day(-1). A balance between phenylalanine intake and the difference between fed and fasted blood phenylalanine concentration was observed at an intake of 20 mg. kg(-1). day(-1). The similarity between these two values (19.5 and 20 mg. kg(-1). day(-1)) suggests that the maximal phenylalanine intake for children with PKU should be no higher than 20 mg. kg(-1). day(-1).     

Late immature mortality is the major influence on reproductive success of African black beetle, Heteronychus arator (Fabricius) (Coleoptera: Scarabaeidae), in a Mediterranean-climate region of Australia

In field and laboratory studies, mortality of African black beetle, Heteronychus arator, in the winter-rainfall, Mediterranean-type climate region of south-western Australia was higher in the late immature stages during summer than in the early immature stages that occur during spring, a contrast to summer-rainfall climatic regions. Greatest mortality occurred around the pupal stage in contrasting soil types, despite drying differences in summer and supplementary watering in some plots. Sampling of natural populations confirmed experimental results that mortality in late immature stages is the major factor limiting H. arator populations under a Mediterranean-type climate. Inter-generation increase in H. arator abundance was uncommon, explaining the consistent abundance typically observed between years in south-western Australia. Random dispersal of newly emerged adults in autumn was inferred to restore uniformity in adult abundance between areas of varying favourability for immature survival.     

A comparison of the metabolism of eighteen-carbon 13C-unsaturated fatty acids in healthy women

Altered use of different dietary fatty acids may contribute to several chronic diseases, including obesity, noninsulin-dependent diabetes mellitus, and cardiovascular disease. However, few comparative data are available to support this link, so the goal of the present study was to compare the metabolism of [(13)C]oleate, [(13)C]alpha-linolenate, [(13)C]elaidate, and [(13)C]linoleate through oxidation and incorporation into plasma lipid fractions and adipose tissue. Each tracer was given as a single oral bolus to six healthy women. Samples were collected over 8 days, and (13)C was analyzed using isotope ratio mass spectrometry. At 9 h postdose, cumulative oxidation was similar for [(13)C]elaidate, [(13)C]oleate, and [(13)C]alpha-linolenate (19 +/- 1%, 20 +/- 4%, and 19 +/- 3% dose, respectively). Significantly lower oxidation of [(13)C]linoleate (12 +/- 4% dose; P < 0.05) was accompanied by its higher incorporation into plasma phospholipids and cholesteryl esters. Abdominal adipose tissue was enriched with [(13)C]alpha-linolenate, [(13)C]elaidate, or [(13)C]linoleate within 6 h. The percentage linoleate in plasma phospholipids correlated positively with [(13)C]linoleate and [(13)C]elaidate oxidation, indicating a potential role of background diet. Conversion of [(13)C]linoleate and [(13)C]alpha-linolenate to longer chain polyunsaturates was a quantitatively minor route of utilization.