Protein Kinase PKR Mediates the Apoptosis Induction and Growth Restriction Phenotypes of C Protein-Deficient Measles Virus

The measles virus (MV) accessory proteins V and C play important roles in MV replication and pathogenesis. Infection with recombinant MV lacking either V or C causes more cell death than infection with the parental vaccine-equivalent virus (MVvac), and C-deficient virus grows poorly relative to the parental virus. Here, we show that a major effector of the C phenotype is the RNA-dependent protein kinase PKR. Using human HeLa cells stably deficient in PKR as a result of RNA interference-mediated knockdown (PKR^kd cells), we demonstrated that a reduction in PKR partially rescued the growth defect of C knockout (C^ko) virus but had no effect on the growth of either wild-type (WT) or V knockout (V^ko) virus. Increased growth of the C^ko virus in PKR^kd cells correlated with increased viral protein expression, while defective growth and decreased protein expression in PKR-sufficient cells correlated with increased phosphorylation of PKR and the α subunit of eukaryotic initiation factor 2. Furthermore, infection with WT, V^ko, or especially C^ko virus caused significantly less apoptosis in PKR^kd cells than in PKR-sufficient cells. Although apoptosis induced by C^ko virus infection in PKR-sufficient cells was blocked by a caspase antagonist, the growth of C^ko virus was not restored to the WT level by treatment with this pharmacologic inhibitor. Taken together, these results indicate that PKR plays an important antiviral role during MV infection but that the virus growth restriction by PKR is not dependent upon the induction of apoptosis. Furthermore, the results establish that a principal function of the MV C protein is to antagonize the proapoptotic and antiviral activities of PKR.     

Orientation and Shape Discrimination in Juveniles and Adults of the Mangrove Crab Aratus pisonii (H. Milne Edwards, 1837): Effect of Predator and Chemical Cues

Behavioral responses of juveniles and adults of the mangrove crab Aratus pisonii (H. Milne Edwards, 1837) to black geometric shapes of equal surface area was measured. Crabs were tested either in presence or absence of chemicals generated from two common predator species, the portunid crab Callinectes ornatus Ordway, and the soapfish Haemulon aurolineatum Cuvier, 1830. The present study tested the hypothesis that A. pisonii (1) has the capacity to orient to visual cues; (2) it discriminates between different visual objects based on a combination of chemical and visual information and (3) this behavior changes with age. When presented with single black targets in background water, juveniles oriented toward all shapes. This behavioral response was interpreted as visual orientation toward potential shelter. Among shapes, juveniles showed preference for the vertical rectangle, probably due to the recognition of natural visual elements like mangrove roots. In predator conditioned water, juveniles exhibited a stronger response than in background water. Thus, juveniles were able to detect by odor the potential presence of predators. Change in responsiveness between adults and juveniles was also demonstrated.     

Is there modal opponency in the thermal senses?

1. 1.The sensations evoked by pairs of distinct thermal stimuli applied to the back of the hand were studied in 17 volunteer subjects. Four stimulus combinations were used; neutral-cold (NC), neutral-neutral (NN), neutral-warm (NW), and cold-warm (CW).

2. 2.The subjects were first asked to estimate the magnitude of the thermal sensations evoked by the thermal stimuli. On average, the four pairs were reported as increasing magnitude in the following order: NC, CW, NN, and NW, seeming to suggest that the subjects experienced the cold-warm combination as a composite sensation of cold and warmth intermediate between pure cold and pure warmth.

3. 3.When asked only to detect the presence of a cold stimulus, the subjects performed as well for the CW combination as for the CN combination. This second result indicates that the reported composite magnitude of CW does not result from a true opponency of cold and warmth but from a cognitive combination of distinct sensations of cold and warmth.

Multimeric bivalent immunogens from recombinant tetanus toxin H<Subscript>C</Subscript> fragment,synthetic hexasaccharides,and a glycopeptide adjuvant

Using recombinant tetanus toxin H_C fragment (rTT-H_C) as carrier, we prepared multimeric bivalent immunogens featuring the synthetic hexasaccharide fragment of O-PS of Vibrio cholerae O:1, serotype Ogawa, in combination with either the synthetic hexasaccharide fragment of O-PS of Vibrio cholerae O:1, serotype Inaba, or a synthetic disaccharide tetrapeptide peptidoglycan fragment as adjuvant. The conjugation reaction was effected by squaric acid chemistry and monitored in virtually real time by SELDI-TOF MS. In this way, we could prepare well-defined immunogens with predictable carbohydrate–carrier ratio, whose molecular mass and the amount of each saccharide attached could be independently determined. The ability to prepare such neoglycoconjugates opens unprecedented possibilities for preparation of conjugate vaccines for bacterial diseases from synthetic carbohydrates.     

In search of specific cytotoxic T lymphocytes infiltrating or accompanying human ovarian carcinoma

Summary Lymphocytes infiltrating human ovarian carcinoma obtained directly from the tumour mass (tumour-infiltrating lymphocytes, TIL) or from the carcinomatous ascites (tumour-associated lymphocytes, TAL) were expanded in vitro in long-term cultures with interleukin-2 and tested for their specific cytolytic activity. Killing of the autologous tumour was detected only in a proportion of the patients, less frequently in TIL compared to TAL. In fact two out of ten TIL and four out of nine TAL cultures tested showed significant levels of lysis against the autologous tumour. This cytotoxic activity was not restricted to the autologous tumour, as other tumour cell lines, including non-ovarian ones, were lysed as well. The cultures that were not cytotoxic against the autologous tumour were in most cases able to lyse other tumour cell lines of ovarian or other histology. Cloning of TIL from one patient was performed: of 22 clones tested, 4 displayed higher cytotoxicity against the autologous tumour compared to the uncloned population and 3 out of these 4 did not kill an irrelevant carcinoma cell line. In order to stimulate the expansion of putative specific effectors we performed mixed lymphocyte/tumour cultures (MLTC) with autologous or allogeneic tumour cells. No stimulation of cytotoxicity against the autologous tumour was detected after MLTC in nine different TAL populations, using autologous or allogeneic tumours as stimulators. On the contrary, peripheral blood lymphocytes from two patients after MLTC with the autologous tumour showed increased killing of the autologous and decreased killing of an allogeneic target. In conclusion TIL and TAL from ovarian carcinoma expanded in vitro with interleukin-2 usually have non-MHC-restricted cytotoxicity and variable degrees of reactivity against the autologous tumour. A preferential killing for the autologous tumour was not observed even after MLTC. These results do not exclude the existence of tumour-specific cytotoxic T lymphocytes in ovarian carcinoma; nevertheless they suggest that putative specific effectors have very low frequency and that culture techniques for expanding their growth more selectively are still to be optimized.     

A nomenclature for the genes encoding the chlorophylla/b-binding proteins of higher plants

We propose a nomenclature for the genes encoding the chlorophylla/b-binding proteins of the light-harvesting complexes of photosystem I and II. The genes encoding LHC I and LHC II polypeptides are namedLhca1 throughLhca4 andLhcb1 throughLhcb6, respectively. The proposal follows the general format recommended by the Commision on Plant Gene Nomenclature. We also present a table for the conversion of old gene names to the new nomenclature.     

Detection of complex alleles by direct analysis of DNA heteroduplexes

DNA molecules derived from three alleles of the HLA-DRB3 locus and differing from each other at several nucleotide sites were denatured and cross-hybridized. Each allelic combination was found to generate a pair of heteroduplexes of different mobility. Their retardation as compared to homoduplexes was proportional to the number of mismatches. In each heteroduplexes pair the component possessing the highest number of Pyr-Pyr oppositions was the most retarded. The results are those predicted by a theoretical model implying a correlation between base-pair opening and bending of the DNA double helix. These observations introduce a new HLA typing method at the genomic level and indicate an experimental approach to the analysis of the superhelical DNA conformation as related to different types of base oppositions.