Effect of photoperiod and temperature on common blight disease of common beans (Phaseolus vulgaris L.)

Summary Although common blight disease is serious in many dry bean production areas, there is only limited information on the influence of photoperiod on the disease. Experiments were conducted in growth chambers and in the field (Nebraska, Dominican Republic, Puerto Rico) to investigate the influence of photoperiod × temperature and photoperiod, respectively, on the reaction of cultivars/lines to the causal bacterium Xanthomonas campestris pv. phaseoli. A split-plot design was used in all experiments except in the DR experiment where cultivars/lines were replicated within each photoperiod treatment. The disease reactions were more severe on cultivars/lines under short photoperiod and under higher temperature than under longer photoperiod and lower temperature in the growth chamber. Disease reactions were also more severe under the short photoperiod in the field experiments. No interactions were detected among these factors. These results have important implications for plant breeders in the evaluation of common blight disease reactions in different latitudes.     

Dust measurements at high ecliptic latitudes

Along Ulysses' path from Jupiter to the south ecliptic pole, the onboard dust detector measured a dust impact rate that varied slowly from 0.2 to 0.5 impacts per day. The dominant component of the dust flux arrived from an ecliptic latitude and longitude of 100 + 10 degrees and 280 degrees +/- 30 degrees which indicates an interstellar origin. An additional flux of small particles, which do not come from the interstellar direction and are unlikely to be zodiacal dust grains, appeared south of -45 degrees latitude. One explanation is that these particles are beta-meteoroids accelerated away from the sun by radiation pressure and electromagnetic forces.     

Thyrocalcitonin: cytological localization by immunofluorescence

Thyrocalcitonin was detected in the cytoplasm of all epithelial cells of the thyroid gland of the pig, by means of antibody fluorescence. It was present in those cells whlich normally elaborate thyroglobulin but was not present in the follicular colloid.     

Organic molecular soft ferromagnetism in a fullerene c60

The properties of an organic molecular ferromagnet [C(60)TDAE(0.86); TDAE is tetrakis(dimethylamino)ethylene] with a Curie temperature ;T(c) = 16.1 kelvin are described. The ferromagnetic state shows no remanence, and the temperature dependence of the magnetization below ;T(c) does not follow the behavior expected of a conventional ferromagnet. These results are interpreted as a reflection of a three-dimensional system leading to a soft ferromagnet.     

A stable aminyl radical metal complex

Metal-stabilized phenoxyl radicals appear to be important intermediates in a variety of enzymatic oxidations. We report that transition metal coordination also supports an aminyl radical, resulting in a stable crystalline complex: [Rh(I)(trop2N.)(bipy)]+OTf- (where trop is 5-H-dibenzo[a,d]cycloheptene-5-yl, bipy is 2,2'-bipyridyl, OTf- is trifluorosulfonate). It is accessible under mild conditions by one-electron oxidation of the amide complex [Rh(I)(trop2N)(bipy)], at a potential of -0.55 volt versus ferrocene/ferrocenium. Both electron paramagnetic resonance spectroscopy and density functional theory support 57% localization of the unpaired spin at N. In reactions with H-atom donors, the Rh-coordinated aminyl behaves as a nucleophilic radical.     

Helix-rod host-guest complexes with shuttling rates much faster than disassembly

Dynamic assembly is a powerful fabrication method of complex, functionally diverse molecular architectures, but its use in synthetic nanomachines has been hampered by the difficulty of avoiding reversible attachments that result in the premature breaking apart of loosely held moving parts. We show that molecular motion can be controlled in dynamically assembled systems through segregation of the disassembly process and internal translation to time scales that differ by four orders of magnitude. Helical molecular tapes were designed to slowly wind around rod-like guests and then to rapidly slide along them. The winding process requires helix unfolding and refolding, as well as a strict match between helix length and anchor points on the rods. This modular design and dynamic assembly open up promising capabilities in molecular machinery.     

Molecular analysis of the sex chromosomes of the platyfish Xiphophorus maculatus: Towards the identification of a new type of master sexual regulator in vertebrates

In contrast to mammals and birds, fish display an amazing diversity of genetic sex determination systems, with frequent changes during evolution possibly associated with the emergence of new sex chromosomes and sex‐determining genes. To better understand the molecular and evolutionary mechanisms driving this diversity, several fish models are studied in parallel. Besides the medaka (Oryzias latipes Temminck and Schlegel, 1846) for which the master sex‐determination gene has been identified, one of the most advanced models for studying sex determination is the Southern platyfish (Xiphophorus maculatus, Günther 1966). Xiphophorus maculatus belongs to the Poeciliids, a family of live‐bearing freshwater fish, including platyfish, swordtails and guppies that perfectly illustrates the diversity of genetic sex‐determination mechanisms observed in teleosts. For X. maculatus, bacterial artificial chromosome contigs covering the sex‐determination region of the X and Y sex chromosomes have been constructed. Initial molecular analysis demonstrated that the sex‐determination region is very unstable and frequently undergoes duplications, deletions, inversions and other rearrangements. Eleven gene candidates linked to the master sex‐determining gene have been identified, some of them corresponding to pseudogenes. All putative genes are present on both the X and the Y chromosomes, suggesting a poor degree of differentiation and a young evolutionary age for platyfish sex chromosomes. When compared with other fish and tetrapod genomes, syntenies were detected only with autosomes. This observation supports an independent origin of sex chromosomes, not only in different vertebrate lineages but also between different fish species.     

Quantification of Common Wheat Adulteration of Durum Wheat Pasta Using Real‐Time Quantitative Polymerase Chain Reaction (PCR)

Common wheat adulteration of durum wheat pasta was quantified using real‐time duplex polymerase chain reaction (PCR). The total DNA content of pasta was determined by amplifying part of a wheat gene encoding a lipid transfer protein, and common wheat DNA was quantified by amplifying part of the puroindoline‐b gene. Under the conditions defined by this study, for pasta with a theoretical adulteration of 3%, the experimentally determined mean value was 2.6–3.4%, depending on drying temperature. Pure durum wheat pastas were distinguished from adulterated pastas without ambiguity. This study demonstrates the feasibility of using real‐time duplex PCR to quantify common wheat adulteration of pasta dried at high temperature, quantification that was impossible with the French official peroxidase‐marker method.