Germination and storage reserve mobilization are regulated independently in Arabidopsis

The phytohormone abscisic acid (ABA) inhibits the germination of many seeds, including Arabidopsis, but the mechanism for this is not known. In cereals, ABA inhibits the expression of genes involved in storage reserve mobilization. We have found that in Arabidopsis ABA decreases transcription from the promoters of marker genes for β-oxidation and the glyoxylate cycle, essential pathways for the conversion of storage lipid (triacylglycerol) into sucrose. Thirty per cent of stored lipid is broken down over 6 days following imbibition of ABA-treated seed. Sucrose levels in ABA-treated seeds, rather than decreasing as under normal growth conditions, actually double during the 3 days following imbibition. This sucrose is derived from triacylglycerol as demonstrated by two mutants disrupted in the conversion of triacylglycerol into sucrose, kat2 and icl1, which do not accumulate sucrose in the presence of ABA. We conclude that the ABA block on germination is not a consequence of inhibition of storage lipid mobilization. Two independent programmes appear to operate, one that is blocked by ABA, governing developmental growth resulting in germination; and a second that governs storage lipid mobilization which is largely ABA-independent

Soviet satellite communications science and technology

This is a report by six US scientists and engineers concerning the current state of the art and projections of future Soviet satellite communications technologies. The panel members are experts in satellite stabilization, spacecraft environments, space power generation, launch systems, spacecraft communications sciences and technologies, onboard processing, ground stations, and other technologies that impact communications. The panel assessed the Soviet ability to support high-data-rate space missions at 128 Mbps by evaluating current and projected Soviet satellite communications technologies. A variety of space missions were considered, including Earth-to-Earth communications via satellites in geostationary or highly elliptical orbits, those missions that require space-to-Earth communications via a direct path and those missions that require space-to-Earth communications via a relay satellite. Soviet satellite communications capability, in most cases, is 10 years behind that of the United States and other industrialized nations. However, based upon an analysis of communications links needed to support these missions using current Soviet capabilities, it is well within the current Soviet technology to support certain space missions outlined above at rates of 128 Mbps or higher, although published literature clearly shows that the Soviet Union has not exceeded 60 Mbps in its current space system. These analyses are necessary but not sufficient to determine mission data rates, and other technologies such as onboard processing and storage could limit the mission data rate well below that which could actually be supported via the communications links. Presently, the Soviet Union appears to be content with data rates in the low-Earth-orbit relay via geostationary mode of 12 Mbps. This limit is a direct result of power amplifier limits, spacecraft antenna size, and the utilization of K{sub u}-band frequencies. 91 refs., 16 figs., 15 tabs

APOE ϵ4, rated life experiences, and affect among centenarians

Additional authors include M. Gearing, W. R. Markesbery, J. S. Tenover, W. L. Rodgers, D. B. Hausman, & C. Rott who are involved with the Georgia Centenarian Study.Objectives: The purpose of this study was to assess the relationship between apolipoprotein E (APOE), life events and engagement, and subjective well-being (as measured by positive and negative affect) among centenarians. Based on the life stress paradigm, we predicted that higher levels of stress would allow APOE to influence positive and negative affect. Method: 196 centenarians and near-centenarians (98 years and older) of the Georgia Centenarian Study participated in this research. The APOE, positive and negative affect, the number of recent (last 2 years) and lifelong (more than 20 years prior to testing) events, as well as a number of life engagement tasks were assessed. Results: Results suggested that centenarians carrying the APOE ϵ4 allele rated lower in positive affect, the number of lifelong events, and in engaged lifestyle, when compared to centenarians without the APOE ϵ4 allele (t = 3.43, p < .01; t = 3.19, p < .01; and t = 2.33, p < .05, respectively). Blockwise multiple regressions indicated that the APOE ϵ4 predicted positive but not negative affect after controlling for demographics. Gene–environment interactions were obtained for the APOE ϵ4 and lifelong events, suggesting that carriers of the APOE ϵ4 allele had higher scores of negative affect after having experienced more events, whereas noncarriers had reduced negative affect levels after having experienced more events. Conclusion: APOE ϵ4 is directly related to positive affect and is related to negative affect in interaction with life events

Outbreak of acupuncture-associated cutaneous Mycobacterium abscessus infections

BACKGROUND: Cutaneous atypical mycobacterial infections have been increasingly described in association with cosmetic and alternative procedures. OBJECTIVE: We report an outbreak of acupuncture-associated mycobacteriosis. Between April and December 2002, 32 patients developed cutaneous mycobacteriosis after visiting an acupuncture practice in Toronto, Canada. RESULTS: Of 23 patients whose lesions were biopsied, 6 (26.1%) had culture-confirmed infection with Mycobacterium abscessus. These isolates were genetically indistinguishable by amplified fragment length polymorphism. The median incubation period was 1 month. Of 24 patients for whom clinical information was available, 23 (95.8%) had resolution of their infection. All patients developed residual scarring or hyperpigmentation. CONCLUSION: Nontuberculous mycobacteria should be recognized as an emerging, but preventable, cause of acupuncture-associated infections