Adenomatous polyposis coli influences micronuclei induction by PhIP and acrylamide in mouse erythrocytes

Micronucleus (MN) induction in erythrocytes of multiple intestinal neoplasia (Min) mice with heterozygous Apc mutation was measured after s.c. injections of acrylamide, glycidamide, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and colchicine, and compared with wild-type (wt) mice. Since Apc influences microtubule dynamics, we wanted to test whether Min-mice were more sensitive to the production of MN than wild-type mice. We also examined the effect of pre-treatment with cytosine β-D-arabinofuranoside (Ara C) and hydroxyurea, which inhibit ligation of DNA strand breaks in the repair of DNA adducts. All compounds induced a significant increase in MN in both strains of mice with the following potencies: acrylamide < glycidamide < PhIP. No difference in the induction of MN was seen between Min-mice and wt-mice exposed to acrylamide, glycidamide or colchicine without pre-treatment. However, in Min-mice, PhIP treatment induced much less MN than in wt-mice, with about four- and six-fold increase in MN in Min-mice and wt-mice, respectively. A reduced ability to repair PhIP adducts may be the reason for the lower induction of MN in Min-mice. Treatment with Ara C and hydroxyurea, to increase sensitivity, gave more than a four-fold increase in MN, but strongly reduced proliferation. Pre-treatment with Ara C and hydroxyurea made the Min-mice slightly more sensitive to MN induction by glycidamide compared to wt-mice. We conclude that Min-mice are less sensitive than wt-mice to MN induction by PhIP that forms bulky DNA adducts, while Min-mice and wt-mice are equally sensitive to MN induction by acrylamide and glycidamide that form DNA base adducts.     

Comparative mapping of mouse and rat chromosomes by fluorescence in situ hybridization

Comparative fluorescence in situ hybridization mapping using DNA libraries from flow-sorted mouse chromosomes and region-specific mouse BAC clones on rat chromosomes reveals chromosomal homologies between mouse (Mus musculus, MMU) and rat (Rattus norvegicus, RNO). Each of the MMU 2, 3, 4, 6, 7, 9, 12, 14, 15, 16, 18, 19, and X chromosomes paints only a single rat chromosome or chromosome segment and, thus, the chromosomes are largely conserved between the two species. In contrast, the painting probes for MMU chromosomes 1, 5, 8, 10, 11, 13, and 17 produce split hybridization signals in the rat, disclosing evolutionary chromosome rearrangements. Comparative mapping data delineate several large linkage groups on RNO 1, 2, 4, 7, and 14 that are conserved in human but diverged in the mouse. On the other hand, there are linkage groups in the mouse, i.e., on MMU 1, 8, 10, and 11, that are disrupted in both rat and human. In addition, we have hybridized probes for Nap2, p57, Igf2, H19, and Sh3d2c from MMU 7 to RNO 1q and found the orientation of the imprinting gene cluster and Sh3d2c to be the same in mouse and rat. Hybridization of rat genomic DNA shows blocks of (rat-specific) repetitive sequences in the pericentromeric region of RNO chromosomes 3-5, 7-13, and 20; on the short arms of RNO chromosomes 3, 12, and 13; and on the entire Y chromosome.     

Long-term studies on genetic interaction between wild and ranched cod Gadus morhua by use of a genetic marked strain

Releases of farmed fish, whether accidental from commercial aquaculture facilities or intentional as part of stock enhancement/ranching activities, are considered to pose a risk to native gene pools. Stock enhancement studies of Atlantic cod, Gadus morhua , based on artificially produced juveniles, were initiated in 1984 in western Norway, and genetic aspects were incorporated. In order to investigate potential interbreeding between released and wild cod, a genetically marked cod strain was developed, being homozygotic for a rare allele ( GPI‐1*30 ) expressed in white muscle tissue. In the period from 1990 to 1994, juveniles from the genetic marked strain were released in large quantities in three locations (Masfjord, Øygarden, Heimarkspollen), giving a significant increase of the marker allele in the local wild cod populations. Recently, studies have been conducted in the same areas to estimate the extent of interbreeding between the wild and released cod. The results, however, revealed no permanent increase of the frequency of the marker allele and/or GPI‐1*30 heterozygotes as would be expected from interbreeding. The recent data are compared with comprehensive genetic data of the cod populations in the areas before the actual releases, covering the full period from 1994 to 2003. The present results are also discussed in relation to fishing pressure on coastal cod, migration information and reproductive success of released, genetically marked cod.     

Assessing the performance of volunteers in monitoring streams

1. Citizens are concerned about the quality of water resources and many participate in monitoring activities, though doubts remain about the quality of the data volunteers collect. We trained volunteers to collect benthic macroinvertebrates using professional protocols. Of the seven stream sites sampled by volunteer crews, six sites were also sampled by professional crews.
2. In the laboratory, volunteers used morphological features to identify as many different taxa as possible within the major insect orders; their identification was approximately to family. Volunteers calculated five metrics: total taxon richness, richness of three key groups (Ephemeroptera, Plecoptera and Trichoptera), and percentage dominance of the three most abundant taxa. All metrics were strongly correlated with (a) the percentage of urbanized area in the catchment and (b) the metrics derived from a more complete taxonomic identification by a professional scientist. Taxon richness metrics declined with urban development, while percent dominance increased.
3. An overall summary multimetric index was used to compare the field and laboratory procedures of volunteers and professionals. Using an ANOVA model, we detected no significant difference between field samples collected by volunteers and professionals. The variance of index values associated with differences between crews was zero. The ability of the index to detect significant differences among sites (statistical power) improved by only 13% for assessments based on professional laboratory identification instead of volunteer laboratory identification.
4. Citizen volunteers, when properly trained, can collect reliable data and make stream assessments that are comparable to those made by professionals. Data collected by volunteers can supplement information used by government agencies to manage and protect rivers and streams.     

Interaction of drought and high temperature on photosynthesis and grain-filling of wheat

Drought and high temperature often occur simultaneously, but their effects on crops are usually investigated individually. Our objective was to compare effects of drought, high temperature, and their interactions on photosynthesis and grain-growth of wheat (Triticum aestivum L.). Plants (cv. Len) were grown uniformly in well-watered soil at 25/20 ± 2 °C day/night until anthesis, when they were subjected to regimes of no drought (soil at field capacity) and drought (plant water potential of –.0 to –2.4 MPa) at 15/10, 25/20, and 35/30 °C in controlled environments until physiological maturity. Drought decreased photosynthesis, stomatal conductance, viable leaf area, shoot and grain mass, and weight and soluble sugar content of kernels but increased plant water-use efficiency. High temperature hastened the decline in photosynthesis and leaf area, decreased shoot and grain mass as well as weight and sugar content of kernels, and reduced water-use efficiency. Interactions between the two stresses were pronounced, and consequences of drought on all physiological parameters were more severe at high temperature than low temperature. The synergistic interactions indicated that productivity of wheat is reduced considerably more by the combined stresses than by either stress alone, and that much of the effect is on photosynthetic processes.     

Spatial and temporal distributions of submarine groundwater discharge rates obtained from various types of seepage meters at a site in the Northeastern Gulf of Mexico

Direct measurements of submarine groundwaterdischarge (SGD) were taken by three different(continuous heat, heat pulse, and ultrasonic)types of automated seepage meters as well asstandard Lee-type manually operated meters. SGD flux comparisons and the spatial andtemporal variations in groundwater flow wereanalyzed. Seepage rates measured by thedifferent meters agree relatively well witheach other (more than 80% agreement). Comparisons of flux rates as a function ofdistance offshore using exponentialapproximations show that more than fivemeasurement locations (200 m offshore) areneeded for a precise integrated estimation ofSGD offshore within an accuracy of ±10%. Thedominant period of seepage variations isestimated to be about 12 hours, which closelymatches the semidiurnal tides in this area. Our analysis also shows that short durationmeasurement periods may cause significantunderestimates or overestimates of the dailyaveraged groundwater flow rates (±25%–±60% difference when the measurement durationis less than 12 hours). Thus, continuousmeasurements of SGD using automated seepagemeters with high time resolution should enableus to evaluate temporal and spatial variationsof dissolved material transports viagroundwater pathways. Such inputs may affectbiogeochemical phenomena in the coastal zone.     

Phylogeny of multidrug transporters.

We currently recognize five large ubiquitous superfamilies and one small eukaryotic-specific family in which cellular multidrug efflux pumps occur. One, the ABC superfamily, includes members that use ATP hydrolysis to drive drug efflux, but the MFS, RND, MATE and DMT superfamilies include members that are secondary carriers, functioning by drug:H(+)or drug:Na(+)antiport mechanisms. The small MET family seems to be restricted to endosomal membranes of eukaryotes, and only a single such system has been functionally characterized. In this review article, these families of drug transporters are discussed and evaluated from phylogenetic standpoints.     

Characterization of a biologically active arabinogalactan from the leaves of Plantago major L.

PMIa is a Type II arabinogalactan with anti-complementary activity isolated from the leaves of Plantago major L. It has a molecular weight of 77000–80000 Da and consists of arabinose (38%), galactose (49%), rhamnose (6%), galacturonic acid (7%) and 1.5% protein with hydroxyproline, alanine and serine as the main amino acids. Characterization of PMIa by methylation and GC-MS, methanolysis and GC, Smith degradation, weak acid hydrolysis, ¹³C-NMR, ¹H-NMR, two-dimensional heteronuclear NMR and DEPT show that it consists of 1,3-linked galactan chains with 1,6-linked galactan side chains attached to position 6. The side chains are further branched in position 3 with 1,3-linked galactose residues which have 1,6-linked galactose attached to position 6; these 1,3- and 1,6-linked galactose chains altogether probably form a network. Terminal and 1,5-linked arabinose in furanose form are attached to the galactan mainly through position 3 of the 1,6-linked galactose side chains.     

Phenotypic Profiling of Scedosporium aurantiacum,an Opportunistic Pathogen Colonizing Human Lungs

Genotyping studies of Australian Scedosporium isolates have revealed the strong prevalence of a recently described species: Scedosporium aurantiacum. In addition to occurring in the environment, this fungus is also known to colonise the respiratory tracts of cystic fibrosis (CF) patients. A high throughput Phenotype Microarray (PM) analysis using 94 assorted substrates (sugars, amino acids, hexose-acids and carboxylic acids) was carried out for four isolates exhibiting different levels of virulence, determined using a Galleria mellonella infection model. A significant difference was observed in the substrate utilisation patterns of strains displaying differential virulence. For example, certain sugars such as sucrose (saccharose) were utilised only by low virulence strains whereas some sugar derivatives such as D-turanose promoted respiration only in the more virulent strains. Strains with a higher level of virulence also displayed flexibility and metabolic adaptability at two different temperature conditions tested (28 and 37°C). Phenotype microarray data were integrated with the whole-genome sequence data of S. aurantiacum to reconstruct a pathway map for the metabolism of selected substrates to further elucidate differences between the strains.     

Purification and characterization of a growth inhibitory hepatic peptide. A preliminary note

A pentapeptide isolated from normal mouse liver seems to inhibit DNA synthesis (3H-thymidine incorporation into liver DNA and labeling indices) and the mitotic rate (G2-M cell flux) in regenerating mouse liver. The inhibitor is somewhat similar to the growth inhibitory pentapeptides previously reported for granulocytes and epidermis. It is active at very low dose levels, showing a bell-shaped dose-response curve.