Autosomal genes of autosomal/X-linked duplicated gene pairs and germ-line proliferation in Caenorhabditis elegans

We report molecular genetic studies of three genes involved in early germ-line proliferation in Caenorhabditis elegans that lend unexpected insight into a germ-line/soma functional separation of autosomal/X-linked duplicated gene pairs. In a genetic screen for germ-line proliferation-defective mutants, we identified mutations in rpl-11.1 (L11 protein of the large ribosomal subunit), pab-1 [a poly(A)-binding protein], and glp-3/eft-3 (an elongation factor 1-α homolog). All three are members of autosome/X gene pairs. Consistent with a germ-line-restricted function of rpl-11.1 and pab-1, mutations in these genes extend life span and cause gigantism. We further examined the RNAi phenotypes of the three sets of rpl genes (rpl-11, rpl-24, and rpl-25) and found that for the two rpl genes with autosomal/X-linked pairs (rpl-11 and rpl-25), zygotic germ-line function is carried by the autosomal copy. Available RNAi results for highly conserved autosomal/X-linked gene pairs suggest that other duplicated genes may follow a similar trend. The three rpl and the pab-1/2 duplications predate the divergence between C. elegans and C. briggsae, while the eft-3/4 duplication appears to have occurred in the lineage to C. elegans after it diverged from C. briggsae. The duplicated C. briggsae orthologs of the three C. elegans autosomal/X-linked gene pairs also display functional differences between paralogs. We present hypotheses for evolutionary mechanisms that may underlie germ-line/soma subfunctionalization of duplicated genes, taking into account the role of X chromosome silencing in the germ line and analogous mammalian phenomena.     

Image plate detectors for macromolecular neutron diffractometry

Neutron diffraction studies of macromolecules require large position sensitive detectors. It is proposed that such a device can be based on image plate technology, which relies on re-usable photostimuable phosphors, combined with a neutron to gamma-ray converter. Design parameters such as the best wavelength for the neutron radiation and the optimum sample to detector distance are discussed, and a design for a cylindrical detector is outlined. Presently a prototype of such a detector is being built, and the very first test-recording of an X-ray diffraction pattern from a protein crystal is presented.     

Role of adenovirus E1B proteins in transformation: altered organization of intermediate filaments in transformed cells that express the 19-kilodalton protein.

Cooperation of the nuclear oncogene E1A with the E1B oncogene is required for transformation of primary cells. Expression vectors were constructed to produce the 19-kilodalton (19K) and 55K E1B proteins under the direction of heterologous promoters in order to investigate the role of individual E1B proteins in transformation. Coexpression of E1A and either the 19K or 55K E1B gene products was sufficient for the formation of transformed foci in primary rat cells at half the frequency of an intact E1B gene, suggesting that the 19K and 55K proteins function via independent pathways in transformation. Furthermore, the effects of Ha-ras and the E1B 19K gene product were additive when cotransfected with E1A, suggesting that the 19K protein functions in transformation by a mechanism independent from that of ras as well. Although expression of E1A and either E1B protein was sufficient for the subsequent growth of cells in long-term culture, the 19K protein was required to support growth in semisolid media. As the 19K protein has been shown to associate with and disrupt intermediate filaments (IFs) when transiently expressed with plasmid vectors (E. White and R. Cipriani, Proc. Natl. Acad. Sci. USA, 86:9886-9890, 1989), the organization of IFs in transformed cells was investigated. Primary rat cells transformed by plasmids encoding E1A plus the E1B 19K protein showed gross perturbations of IFs, whereas cell lines transformed by plasmids encoding E1A plus the E1B 55K protein or E1A plus Ha-ras did not. These results suggest that an intact IF cytoskeleton may inhibit anchorage-independent growth and that the E1B 19K protein can overcome this inhibition by disrupting the IF cytoskeleton.     

Pseudomonas aeruginosa antibody detection in cystic fibrosis patients.

Chronic respiratory infection due to Pseudomonas aeruginosa remains the most important prognostic factor in cystic fibrosis patients. One method to lengthen the patient's life is to extend the initial state of the illness with an early diagnosis, before Ps. aeruginosa infection becomes chronic. Often this is difficult because of the young age of the patients. This study tested an immunoenzymatic system to evaluate antibody response against three Ps. aeruginosa purified antigens, alkaline protease, elastase and exotoxin A. We studied 40 patients with cystic fibrosis, 20 affected and 20 unaffected by apparent Ps. aeruginosa infection, also from the bacteriological point of view. Serological and bacteriological results were compared for each patient and showed that serological screening can be useful in young subjects, who often have no bacteriological evidence of Ps. aeruginosa colonization.     

Rhamnogalacturonan from Acmella oleracea (L.) R.K. Jansen: Gastroprotective and Ulcer Healing Properties in Rats

A rhamnogalacturonan (RGal) isolated from Acmella oleracea (L.) R.K. Jansen administered by oral route showed gastroprotective activity against acute lesions induced by ethanol. In this study, we investigated the gastric ulcer healing effect of RGal and its mechanisms of action. Intraperitoneal treatment of animals with RGal protected the gastric mucosa against acute lesions induced by ethanol, with participation of gastric mucus. Furthermore, in the chronic ulcer model, oral administration of RGal accelerates the gastric ulcer healing, accompanied by increasing of cellular proliferation and gastric mucus content, reducing inflammatory parameters and oxidative stress. In addition, the repeated 7 days-treatment of animals with RGal did not show alterations of clinical and behavioral symptoms, body and organs weights or plasmatic biochemical parameters. Collectively, these results showed that RGal has an interesting antiulcerogenic activity and could constitute an attractive molecule of interest for the development of new antiulcer agents.     

Vibrotactile Sensory Substitution Elicits Feeling of Ownership of an Alien Hand

Tactile feedback plays a key role in the attribution of a limb to the self and in the motor control of grasping and manipulation. However, due to technological limits, current prosthetic hands do not provide amputees with cutaneous touch feedback. Recent findings showed that amputees can be tricked into experiencing an alien rubber hand as part of their own body, by applying synchronous touches to the stump which is out of view, and to the rubber hand in full view. It was suggested that similar effects could be achieved by using a prosthesis with touch sensors that provides synchronous cutaneous feedback through an array of tactile stimulators on the stump. Such a prosthesis holds the potential to be easily incorporated within one’s body scheme, because it would reproduce the perceptual illusion in everyday usage. We propose to use sensory substitution – specifically vibrotactile – to address this issue, as current haptic technology is still too bulky and inefficient. In this basic study we addressed the fundamental question of whether visuo-tactile modality mismatch promotes self-attribution of a limb, and to what extent compared to a modality-matched paradigm, on normally-limbed subjects. We manipulated visuo-tactile stimulations, comprising combinations of modality matched, modality mismatched, synchronous and asynchronous stimulations, in a set of experiments fashioned after the Rubber Hand Illusion. Modality mismatched stimulation was provided using a keypad-controlled vibrotactile display. Results from three independent measures of embodiment (questionnaires, pointing tests and skin conductance responses) indicate that vibrotactile sensory substitution can be used to induce self-attribution of a rubber hand when synchronous but modality-conflicting visuo-tactile stimulation is delivered to the biological finger pads and to the equivalent rubber hand phalanges.     

The development of a bin mapping population and the selective mapping of 103 markers in the diploid Fragaria reference map.

We have identified a set of plants (the bin set) to permit "selective" or "bin" mapping using the diploid strawberry mapping population FV x FN, derived from the F2 cross F. vesca 815 x F. nubicola 601, which has been used to develop the Fragaria reference map. The bin set consists of 8 plants: the F. vesca 815 parent, the F1 hybrid individual, and 6 seedlings of the F2 population. This bin set divides the 578 cM of the diploid Fragaria genome into 46 bins, the largest mapping bin being 26 cM in length and the average bin size being 12.6 cM. To validate the FV x FN bin set, we used it to locate 103 loci into bins on the FV x FN map. These loci comprised 61 previously described SSRs, 38 new SSRs developed in this investigation from Fragaria x ananassa genomic DNA, EST and gene sequences, and 4 ripening-related genes developed for Prunus. The 103 markers were located to bins on all 7 linkage groups of the Fragaria map and a new mapping bin was identified with the novel markers, demonstrating that the map covers the majority of the diploid Fragaria genome and that the 6 bin-set seedlings selected were appropriate for bin mapping using this progeny.