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1.
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.
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2.
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.
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4.
JN Matthiessen 《Australian Journal of Entomology》1999,38(4):348-353
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. 相似文献
5.
Hollamby S Afema-Azikuru J Sikarskie JG Stuht JN Bowerman WW Kaneene JB Fitzgerald SD Cameron K Gandolf AR Hui GN Dranzoa C Rumbeiha WK 《Journal of wildlife diseases》2004,40(3):594-599
Packed cell volumes (PCV) and plasma chemistry parameters were measured in 20 nestling marabou storks (Leptoptilos crumeniferus) in January 2003 that were a part of a colony located in the center of the city of Kampala, Uganda. There were no significant differences (P> or =0.05) in plasma chemistry values or PCV between sexes with the exception of globulin and total plasma protein values, which were higher in females. There were significant differences (P< or =0.05) in blood glucose, creatine kinase, and globulin levels between birds of different body weight. Total plasma protein, uric acid, phosphorous, and creatine kinase were generally higher relative to published data on other avian species, including nestling white storks (Ciconia ciconia). 相似文献
6.
BRCA1 C-terminal (BRCT) domains are integral signaling modules in the DNA damage response (DDR). Aside from their established roles as phospho-peptide binding modules, BRCT domains have been implicated in phosphorylation-independent protein interactions, DNA binding and poly(ADP-ribose) (PAR) binding. These numerous functions can be attributed to the diversity in BRCT domain structure and architecture, where domains can exist as isolated single domains or assemble into higher order homo- or hetero-domain complexes. In this review, we incorporate recent structural and biochemical studies to demonstrate how structural features allow single and tandem BRCT domains to attain a high degree of functional diversity.Key words: BRCT domain, DNA repair, phosphorylation, phospho-peptide interaction, protein interaction, DNA binding, DNA damage response 相似文献
7.
Ogden LG Stroebele N Wyatt HR Catenacci VA Peters JC Stuht J Wing RR Hill JO 《Obesity (Silver Spring, Md.)》2012,20(10):2039-2047
The National Weight Control Registry (NWCR) is the largest ongoing study of individuals successful at maintaining weight loss; the registry enrolls individuals maintaining a weight loss of at least 13.6 kg (30 lb) for a minimum of 1 year. The current report uses multivariate latent class cluster analysis to identify unique clusters of individuals within the NWCR that have distinct experiences, strategies, and attitudes with respect to weight loss and weight loss maintenance. The cluster analysis considers weight and health history, weight control behaviors and strategies, effort and satisfaction with maintaining weight, and psychological and demographic characteristics. The analysis includes 2,228 participants enrolled between 1998 and 2002. Cluster 1 (50.5%) represents a weight-stable, healthy, exercise conscious group who are very satisfied with their current weight. Cluster 2 (26.9%) has continuously struggled with weight since childhood; they rely on the greatest number of resources and strategies to lose and maintain weight, and report higher levels of stress and depression. Cluster 3 (12.7%) represents a group successful at weight reduction on the first attempt; they were least likely to be overweight as children, are maintaining the longest duration of weight loss, and report the least difficulty maintaining weight. Cluster 4 (9.9%) represents a group less likely to use exercise to control weight; they tend to be older, eat fewer meals, and report more health problems. Further exploration of the unique characteristics of these clusters could be useful for tailoring future weight loss and weight maintenance programs to the specific characteristics of an individual. 相似文献
8.
Donahoo W Wyatt HR Kriehn J Stuht J Dong F Hosokawa P Grunwald GK Johnson SL Peters JC Hill JO 《Obesity (Silver Spring, Md.)》2008,16(1):64-69
Objective: The fat content of a diet has been shown to affect total energy intake, but controlled feeding trials have only compared very high (40% of total calories) fat diets with very low (20% of total calories) fat diets. This study was designed to measure accurately the voluntary food and energy intake over a range of typical intake for dietary fat. Methods and Procedures: Twenty‐two non‐obese subjects were studied for 4 days on each of three diets, which included core foods designed to contain 26, 34, and 40% fat, respectively of total calories and ad lib buffet foods of similar fat content. All diets were matched for determinants of energy density except dietary fat. Subjects consumed two meals/day in an inpatient unit and were provided the third meal and snack foods while on each diet. All food provided and not eaten was measured by research staff. Results: Voluntary energy intake increased significantly as dietary fat content increased (P = 0.008). On the 26% dietary fat treatment, subjects consumed 23.8% dietary fat (core and ad lib foods combined) and 2,748 ± 741 kcal/day (mean ± s.d.); at 34% dietary fat, subjects consumed 32.7% fat and 2,983 ± 886 kcal/day; and at 40% dietary fat subjects consumed 38.1% fat and 3,018 ± 963 kcal/day. Discussion: These results show that energy intake increases as dietary fat content increases across the usual range of dietary fat consumed in the United States. Even small reductions in dietary fat could help in lowering total energy intake and reducing weight gain in the population. 相似文献
9.
Florian Ryffel Eric JN Helfrich Patrick Kiefer Lindsay Peyriga Jean-Charles Portais J?rn Piel Julia A Vorholt 《The ISME journal》2016,10(3):632-643
The phyllosphere, which is defined as the parts of terrestrial plants above the ground, is a large habitat for different microorganisms that show a high extent of adaption to their environment. A number of hypotheses were generated by culture-independent functional genomics studies to explain the competitiveness of specialized bacteria in the phyllosphere. In contrast, in situ data at the metabolome level as a function of bacterial colonization are lacking. Here, we aimed to obtain new insights into the metabolic interplay between host and epiphytes upon colonization of Arabidopsis thaliana leaves in a controlled laboratory setting using environmental metabolomics approaches. Quantitative nuclear magnetic resonance (NMR) and imaging high-resolution mass spectrometry (IMS) methods were used to identify Arabidopsis leaf surface compounds and their possible involvement in the epiphytic lifestyle by relative changes in compound pools. The dominant carbohydrates on the leaf surfaces were sucrose, fructose and glucose. These sugars were significantly and specifically altered after epiphytic leaf colonization by the organoheterotroph Sphingomonas melonis or the phytopathogen Pseudomonas syringae pv. tomato, but only to a minor extent by the methylotroph Methylobacterium extorquens. In addition to carbohydrates, IMS revealed surprising alterations in arginine metabolism and phytoalexin biosynthesis that were dependent on the presence of bacteria, which might reflect the consequences of bacterial activity and the recognition of not only pathogens but also commensals by the plant. These results highlight the power of environmental metabolomics to aid in elucidating the molecular basis underlying plant–epiphyte interactions in situ. 相似文献
10.