When contemporary aminoacyl-tRNA synthetases invent their cognate amino acid metabolism.

Faithful protein synthesis relies on a family of essential enzymes called aminoacyl-tRNA synthetases, assembled in a piecewise fashion. Analysis of the completed archaeal genomes reveals that all archaea that possess asparaginyl-tRNA synthetase (AsnRS) also display a second ORF encoding an AsnRS truncated from its anticodon binding-domain (AsnRS2). We show herein that Pyrococcus abyssi AsnRS2, in contrast to AsnRS, does not sustain asparaginyl-tRNAAsn synthesis but is instead capable of converting aspartic acid into asparagine.

Non-discriminating and discriminating aspartyl-tRNA synthetases differ in the anticodon-binding domain.

In most organisms, tRNA aminoacylation is ensured by 20 aminoacyl-tRNA synthetases (aaRSs). In eubacteria, however, synthetases can be duplicated as in Thermus thermophilus, which contains two distinct AspRSs. While AspRS-1 is specific, AspRS-2 is non-discriminating and aspartylates tRNA(Asp) and tRNA(Asn).

Effect of spatial heterogeneity on the role of Coccinella septempunctata as an intra-guild predator of the aphid pathogen Pandora neoaphidis.

The foraging behavior of starved and non-starved adult and larval Coccinella septempunctata on groups of plants in the presence of Pandora neoaphidis-infected Acyrthosiphon pisum, uninfected aphids or a mixture of these two prey types was compared. In general results of these studies confirmed the results of previous work comparing foraging behavior on a smaller spatial scale in Petri dishes. However, behaviors were modified in response to spatial complexity, prey quality, and the host plant.

Ethanol promotes intestinal tumorigenesis in the MIN mouse. Multiple intestinal neoplasia.

Epidemiological studies suggest that alcohol consumption increases the risk of developing colorectal cancer; however, these data are confounded by numerous cosegregating variables. Previous experimental reports with the rodent carcinogen model have also yielded discordant results. To clarify the alcohol-colon cancer relationship, we used the MIN (multiple intestinal neoplasia) mouse, a genetic model of intestinal tumorigenesis.

Effect on body weight of replacing dietary fat with olestra for two or ten weeks in healthy men and women.

Objective: To examine in two separate studies the effects of replacing dietary fat with Olestra on body composition and weight change in healthy young men and women.

Methods: Ten healthy, lean young men participated in Study One that was a 22-day single blind, within-subject design. After a control diet (40% fat) for eight days Study One subjects received an Olestra-substituted diet (31% metabolizable fat) for 14 days.

AKT proto-oncogene overexpression is an early event during sporadic colon carcinogenesis.

The inhibition of apoptosis is a critical event in the development of colorectal malignancies, although the mechanism(s) remain incompletely understood. The anti-apoptotic proto-oncogene, AKT, has been implicated in the molecular pathogenesis of a variety of human malignancies; however, no data exist on the role of AKT in colon carcinogenesis. We therefore evaluated the presence of AKT in human and experimental colon neoplasms by immunohistochemistry.

Colorectal cancer screening compliance by medicine residents: perceived and actual.

Objective: Implementation of colorectal cancer (CRC) screening with widely available techniques can result in a significant reduction in CRC-related mortality. Clinical practice paradigms are often ingrained in physicians during residency. We, therefore, investigated both compliance and perceived obstacles to CRC screening in the practices of physicians-in-training.

Crystallization and preliminary X-ray diffraction data of the second and archaebacterial-type aspartyl-tRNA synthetase from Thermus thermophilus.

The archaebacterial-type aspartyl-tRNA synthetase (AspRS2) from the thermophilic eubacterium Thermus thermophilus was crystallized using the hanging-drop vapour-diffusion method. Crystals grew at pH 9.5 in the presence of PEG 8000 and NaCl.

Prediction of energy expenditure in a whole body indirect calorimeter at both low and high levels of physical activity.

Objectives: In studies that involve the use of a room calorimeter, 24 h energy intake is often larger than 24 h energy expenditure (24 h EE) because of a decrease in activity energy expenditure due to the confined space. This positive energy balance can have large consequences for the interpretation of substrate balances. The objective of this study was to develop a method for predicting an individual's 24 h EE in a room calorimeter at both low (1.

Polyethylene glycol induces apoptosis in HT-29 cells: potential mechanism for chemoprevention of colon cancer.

Recent experimental evidence suggests that polyethylene glycol (PEG) is a highly effective chemopreventive agent against colon cancer; however, the mechanism(s) remain largely unexplored. To further elucidate this issue, we evaluated the effect of PEG on two human colon cancer cell lines. PEG treatment resulted in a dose- and time-dependent reduction in cell number without alteration in markers of cell proliferation.

Chemoprevention of intestinal tumorigenesis by nabumetone: induction of apoptosis and Bcl-2 downregulation.

Treatment of MIN mice with the nonsteroidal anti-inflammatory drug, nabumetone, resulted in a dose-dependent suppression of intestinal tumorigenesis. In both the uninvolved MIN mouse colonic epithelium and HT-29 colon cancer cells, nabumetone downregulated the anti-apoptotic protein, Bcl-2, with concomitant induction of apoptosis, suggesting a potential mechanism for colon cancer chemoprevention.

Distal bowel selectivity in the chemoprevention of experimental colon carcinogenesis by the non-steroidal anti-inflammatory drug nabumetone.

Use of non-steroidal anti-inflammatory drugs (NSAIDs) for chemoprevention of colon cancer has been hindered by their potential gastro-intestinal toxicity. Nabumetone, which is approximately 10 to 36 times safer than conventional NSAIDs, was evaluated in 2 models of experimental colon carcinogenesis. In azoxymethane (AOM)-treated Fisher 344 rats, nabumetone caused dose-dependent inhibition of aberrant crypt foci (ACF), with 750 and 1,500 ppm resulting in 15% and 37% reductions, respectively (p < 0.

Ankle images digital analysis (AIDA): digital measurement of joint space width and subchondral sclerosis on standard radiographs.

Objective: Reliable evaluation of joint space width and subchondral sclerosis of osteoarthritic joints is difficult. The present study describes a new digital method to analyse standard radiographs of the ankle.

Design: Standardized radiographs were taken of the ankle of 12 patients with severe osteoarthritis (OA) under full weight-bearing conditions, before treatment and 1 year after initiation of treatment.

The heterotrimeric Thermus thermophilus Asp-tRNA(Asn) amidotransferase can also generate Gln-tRNA(Gln).

Thermus thermophilus strain HB8 is known to have a heterodimeric aspartyl-tRNA(Asn) amidotransferase (Asp-AdT) capable of forming Asn-tRNA(Asn) [Becker, H.D. and Kern, D.

Concurrent physical activity increases fat oxidation during the shift to a high-fat diet.

Background: It takes several days to adapt to a high-fat diet. In an earlier study, we observed a large degree of interindividual variation in the capacity to adapt to a high-fat diet. We hypothesized that concurrent physical activity would accelerate fat oxidation during an isoenergetic high-fat diet.

Thermus thermophilus contains an eubacterial and an archaebacterial aspartyl-tRNA synthetase.

Thermus thermophilus possesses two aspartyl-tRNA synthetases (AspRSs), AspRS1 and AspRS2, encoded by distinct genes. Alignment of the protein sequences with AspRSs of other origins reveals that AspRS1 possesses the structural features of eubacterial AspRSs, whereas AspRS2 is structurally related to the archaebacterial AspRSs. The structural dissimilarity between the two thermophilic AspRSs is correlated with functional divergences.

Fat and carbohydrate balances during adaptation to a high-fat.

Background: Dietary fat contents are highly variable. Failure to compensate for the positive fat balance that occurs during the shift to a high-fat, low-carbohydrate diet by increasing energy expenditure or by decreasing food intake may result in the gain of fat mass.

Objective: The objective of this study was to investigate the time course of fat oxidation during adaptation to an isoenergetic high-fat, low-carbohydrate diet.

tRNA glycylation system from Thermus thermophilus. tRNAGly identity and functional interrelation with the glycylation systems from other phylae.

The systems of tRNA glycylation belong to the most complex aminoacylation systems since neither the oligomeric structure of glycyl-tRNA synthetases (GlyRS) nor the discriminator bases in tRNAGly are conserved in the phylae. To better understand the structure-function relationship in glycylation systems of various origins and the functional peculiarities related to their structural divergences, the elements in tRNA conferring its glycine identity in Thermus thermophilus were characterized and compared to those of other systems. Thermophilic identity is conferred by the G1-C72, C2-G71, G3-C70, and C50-G64 pairs together with the G10, U16, C35, and C36 single residues.

Effects of fungal infection on the alarm response of pea aphids.

Pea aphids (Acyrthosiphon pisum, Homoptera: Aphididae) infected with the fungal pathogen Erynia neoaphidis (Zygomycetes: Entomophthorales) were less sensitive to the aphid alarm pheromone (E)-beta-farnesene than uninfected aphids. Approximately 83% of the healthy aphids and 45% of the infected aphids (2 and 3 days post-inoculation) responded to the alarm pheromone. The percentage of nonresponding aphids increased as the disease progressed.

Implications of predator foraging on aphid pathogen dynamics.

The foraging behavior of starved and nonstarved second and fourth instar Coccinella septempunctata larvae on dead Acyrthosiphon pisum aphids, either infected with the entomopathogenic fungus Erynia neoaphidis (sporulating) or uninfected, was examined. Larvae searched for longer and fed less when presented with infected rather than uninfected A. pisum.