The complete nucleotide sequence of an infectious clone of cauliflower mosaic virus by M13mp7 shotgun sequencing.

We have determined the complete primary structure (8031 base pairs) of an infectious clone of cauliflower mosaic virus strain CM1841. The sequence was obtained using the strategy of cloning shotgun restriction fragments in the sequencing vector M13mp7. Comparison of the CM1841 sequence with that published for another caMV strain (Strasbourg) reveals 4.4% changes, mostly nucleotide substitutions with a few small insertions and deletions. The six open reading frames in the sequence of the Strasbourg isolate are also present in CM1841.     

Endosperm-specific demethylation and activation of specific alleles of α-tubulin genes of Zea mays L.

We have investigated the methylation status of the α-tubulin genes, and the degree of accumulation of their mRNAs in endosperm, embryo and seedling tissues of Zea mays L. We have found that many of the α-tubulin genes are differentially demethylated in the endosperm relative to the embryo and seedling. However, only for tubα2 and tubα4 could a correlation between DNA demethylation and increased RNA accumulation be detected. By analyzing the inbred lines W64A and A69Y and their reciprocal crosses, we have also identified in the endosperm two α-tubulin genes, tubα3 and tubα4, that are differentially demethylated if transmitted by the maternal germline, but that remain hypermethylated when transmitted by the paternal germline.     

In vivo mutant frequency rises among breast cancer patients after exposure to high doses of gamma-radiation

Human in vivo mutant frequencies can be measured by cloning freshly isolated lymphocytes in selective media containing 6-thioguanine (TG). This method was applied to monitoring environmental mutagenesis, by studying lymphocytes separated from peripheral blood of 12 cancer patients undergoing radiotherapy. Before therapy, cancer patients had an average 8.6 X 10(-6) mutants/cell, compared to 2.4 X 10(-6) mutants/cell for heart patients and 1.1 X 10(-6) mutants/cell for healthy controls. After exposure of cancer patients to 50 Gy of gamma-radiation delivered to the treated area, or an estimated 4 Gy received by each lymphocyte, patients averaged 36.8 X 10(-6) mutants/viable cell.     

Dual transgenic reporter mice as a tool for monitoring expression of glial fibrillary acidic protein

Glial fibrillary acidic protein (GFAP) is the major intermediate filament protein of astrocytes, and its expression changes dramatically during development and following injury. To facilitate study of the regulation of GFAP expression, we have generated dual transgenic mice expressing both firefly luciferase under the control of a 2.2 kb human GFAP promoter and Renilla luciferase under the control of a 0.5 kb human Glyceraldehyde 3 phosphate dehydrogenase (GAPDH) promoter for normalization of the GFAP signal. The GFAP-fLuc was highly expressed in brain compared to other tissues, and was limited to astrocytes, whereas the GAPDH-RLuc was more widely expressed. Normalization of the GFAP signal to the GAPDH signal reduced the inter-individual variability compared to using the GFAP signal alone. The GFAP/GAPDH ratio correctly reflected the up-regulation of GFAP that occurs following retinal degeneration in FVB/N mice because of the rd mutation. Following kainic acid-induced seizures, changes in the GFAP/GAPDH ratio precede those in total GFAP protein. In knock-in mice expressing the R236H Alexander disease mutant, GFAP promoter activity is only transiently elevated and may not entirely account for the accumulation of GFAP protein that takes place.     

Neonatal opiate withdrawal alters the reactivity of adult rats to the hot-plate

Prenatal exposure of rats to 0.2 mg LAAM/kg/day but not to 0.05 mg LAAM/kg/day resulted in faster hot-plate escape latencies in 6 mo old offspring. No differences in tail-flick latencies were observed at 7 mo of age in offspring exposed to either dose of LAAM prenatally. Subsequent testing of littermates at 16 mo of age revealed that the greater sensitivity to the hot-plate observed in rats prenatally exposed to LAAM is apparently a result of neonatal withdrawal rather than a primary consequence of the drug. The data are discussed in relation to possible effects of drug or withdrawal on central nervous system development.     

In situ stalk growth rates in tropical western Atlantic sea lilies (Echinodermata: Crinoidea)

Despite their greater familiarity as fossils, stalked crinoids, or sea lilies, remain important components of hard-substrate assemblages at bathyal depths in both tropical western Atlantic and Pacific regions. To determine stalk growth rates, specimens collected along the western margin of Little Bahama Bank using the submersibles Johnson Sea Link I and II were measured, tagged with color-coded cable ties, returned to the sea floor either to the site at which they were collected or to different habitats or depths, and recovered several months to over a year later. This paper examines stalk growth rates in Neocrinus decorus, Cenocrinus asterius, and the subspecies of Endoxocrinus parrae (E. parrae parrae, E. parrae prionodes and E. parrae carolinae) and their variations relative to depth and current flow. Studies were carried out at three different depth sites: 249 m, 372-435 m and 540-576 m. N. decorus produces substantially more stalk per year than any subspecies of E. parrae or C. asterius (10-17 cm y^− 1 versus no more than 3.6 cm y^− 1) but contributes no more than twice as much skeletal volume to the sediment because of its more slender stalk. To examine environmental control of growth, E. parrae parrae was transplanted beyond its local depth range to the habitat at which deeper-dwelling E. parrae prionodes occurs (572 m). E. parrae parrae grew at 0.6 ± 0.4 cm y^− 1 (n = 6) here, significantly more slowly than in 404 m and more slowly than E. parrae prionodes (2.1 ± 0.6 cm y^− 1; n = 4), supporting the hypothesis that these two morphs exhibit distinct growth strategies. Growth rates for E. parrae parrae and N. decorus do not differ significantly between adjacent high and lower current-velocity habitats at the same depth, although both exhibit significantly shorter stalk lengths and crown elevations on raised topography apparently subject to stronger flow.     

The manipulation of zein genes to improve the nutritional value of corn

The zein genes from corn (maize) were among the first plant genes to be isolated by recombinant DNA techniques. They encode a set of proteins which are of agricultural importance. Over 2 billion bushels of corn are fed to poultry and pigs each year in the USA alone. However the nutritional balance of corn is not ideal and thus farmers must buy expensive feed supplements. By changing the composition of zein proteins, genetic engineers might produce savings of many million dollars a year.     

Lebenslust und Fremdenfurcht: Ethnologie im Dritten Reich

Lebenslust und Fremdenfurcht: Ethnologie im Dritten Reich. Thomas Hauschild. ed. Frankfurt am Main, Germany: Suhrkamp, 1995. 224 pp.     

Functional shifts in the use of parasitized hosts by a tephritid fly: the role of host quality

Superparasitism, a phenomenon in which parasitic insects layeggs in already-exploited hosts, provides a useful context inwhich to examine the dynamics of parental investment. This studyexplored conditions under which female Mediterranean fruit flies(Ceratitis capitata) shift from avoiding superparasitism ofhost fruit to preferring it, even placing eggs direcdy intoexisting egg-laying cavities. An a priori hypothesis of costsand benefits was used to predict how use and avoidance of parasitizedfruit would change in -response to changes in fruit size andripeness. We predicted that avoidance would decrease with increasingfruit size, while use would increase with decreasing ripeness.Using a field-cage assay, ripeness was held constant and thesize of host coffee berries manipulated. Avoidance of parasitizedberries was significandy less pronounced on large berries thanon small ones. In a second experiment, size was held constantand ripeness manipulated. On unripe berries, females depositedthe majority of clutches directly into existing egg-laying cavities.On ripe berries, by contrast, the same females deposited mostclutches in previously unparasitized fruit. Parallel patternsin the frequency of female-female contests were observed, supportingthe notion that a fruit's value is determined by an interactionbetween fruit size or ripeness, on one hand, and the prior occurrenceof eggs, on the other. Laboratory assays suggested that useof existing sites had advantages in terms of time savings; femalebehavior thus constitutes a relatively uncommon example of adaptivesuperparasitism in which parasitized hosts are actually preferredover unparasitized ones.[Behav Ecol 7: 235-242 (1996)]