Are capuchin monkeys (Cebus apella) inequity averse?

It has been reported that capuchin monkeys reject a less preferred food (LPF) when they see a partner capuchin receive a more preferred food (PF) for performing the same task. This behaviour was taken as evidence of 'inequity aversion', but an alternative hypothesis is that capuchins reject the LPF because of the mere presence of the PF. We tested this hypothesis in a paradigm, which consisted of presenting two different foods (one PF and one LPF) on a tray and allowing the capuchin to take only the LPF. Refusals to initiate the trial and refusals to take and eat the LPF were higher when the PF was hidden (hiding condition) and when the PF was accumulated in sight but out of reach of the subject (accumulation condition) compared to when two pieces of LPF were placed on the tray (control condition). Interestingly, the subject behaved as in the control condition when its partner was given and ate the PF (partner condition). We argue that capuchins' refusals were due to the frustration of seeing and not obtaining the PF, and that seeing the partner eating increases the LPF acceptance.     

Suppressor of cytokine signaling 1 interacts with the macrophage colony-stimulating factor receptor and negatively regulates its proliferation signal

Macrophage colony-stimulating factor receptor (M-CSF-R) is a tyrosine kinase that regulates proliferation, differentiation, and cell survival during monocytic lineage development. Upon activation, M-CSF-R dimerizes and autophosphorylates on specific tyrosines, creating binding sites for several cytoplasmic SH2-containing signaling molecules that relay and modulate the M-CSF signal. Here we show that M-CSF-R interacts with suppressor of cytokine signaling 1 (Socs1), a negative regulator of various cytokine and growth factor signaling pathways. Using the yeast two-hybrid system, in vitro glutathione S-transferase-M-CSF-R pull-down, and in vivo coimmunoprecipitation experiments, we demonstrated a direct interaction between the SH2 domain of Socs1 and phosphorylated tyrosines 697 or 721 of the M-CSF-R kinase insert region. Moreover, Socs1 is tyrosine-phosphorylated in response to M-CSF. Ectopic expression of Socs1 in FDC-P1/MAC and EML hematopoietic cell lines decreased their growth rates in the presence of limiting concentrations of M-CSF. However, Socs1 expression did not totally suppress long term cell growth in the presence of saturating M-CSF concentrations, in contrast to other cytokines such as stem cell factor and interleukin 3. Taken together, these results suggest that Socs1 is an M-CSF-R-binding partner involved in negative regulation of proliferation signaling and that it differentially affects cytokine receptor signals.     

Genome-wide association and genomic prediction for host response to porcine reproductive and respiratory syndrome virus infection

Background

Host genetics has been shown to play a role in porcine reproductive and respiratory syndrome (PRRS), which is the most economically important disease in the swine industry. A region on Sus scrofa chromosome (SSC) 4 has been previously reported to have a strong association with serum viremia and weight gain in pigs experimentally infected with the PRRS virus (PRRSV). The objective here was to identify haplotypes associated with the favorable phenotype, investigate additional genomic regions associated with host response to PRRSV, and to determine the predictive ability of genomic estimated breeding values (GEBV) based on the SSC4 region and based on the rest of the genome. Phenotypic data and 60 K SNP genotypes from eight trials of ~200 pigs from different commercial crosses were used to address these objectives.

Results

Across the eight trials, heritability estimates were 0.44 and 0.29 for viral load (VL, area under the curve of log-transformed serum viremia from 0 to 21 days post infection) and weight gain to 42 days post infection (WG), respectively. Genomic regions associated with VL were identified on chromosomes 4, X, and 1. Genomic regions associated with WG were identified on chromosomes 4, 5, and 7. Apart from the SSC4 region, the regions associated with these two traits each explained less than 3% of the genetic variance. Due to the strong linkage disequilibrium in the SSC4 region, only 19 unique haplotypes were identified across all populations, of which four were associated with the favorable phenotype. Through cross-validation, accuracies of EBV based on the SSC4 region were high (0.55), while the rest of the genome had little predictive ability across populations (0.09).

Conclusions

Traits associated with response to PRRSV infection in growing pigs are largely controlled by genomic regions with relatively small effects, with the exception of SSC4. Accuracies of EBV based on the SSC4 region were high compared to the rest of the genome. These results show that selection for the SSC4 region could potentially reduce the effects of PRRS in growing pigs, ultimately reducing the economic impact of this disease.     

Evaluation of a DNA pooled-sampling strategy for estimating the RFLP diversity of maize populations

Molecular characterization by means of RFLPs of large sets of populations is presently limited by experimental costs. In order to reduce costs, we have evaluated a method based on the RFLP analysis of balanced bulks of DNA from several individuals. The precision of this approach for estimating allele frequencies within each population was investigated using (i) DNA extracted from controlled bulks of leaf tissues of maize inbred lines, (ii) data obtained from individual analyses of 10 maize populations. Both approaches showed that allele frequencies can generally be estimated with a high precision (coefficients of determination up to 0.99 for some probe-enzyme combinations assayed), relative to the variation in allele frequencies observed among maize populations. Although further efforts are needed to define a set of probe-enzyme combinations that can be routinely image processed, these results, and preliminary results from a 65 maize populations project, suggest that this approach could provide highly informative data for large sets of populations, and at relatively low costs.     

Inhibition of Adherence of Actinobacillus pleuropneumoniae to Porcine Respiratory Tract Cells by Monoclonal Antibodies Directed Against LPS and Partial Characterization of the LPS Receptors

Actinobacillus pleuropneumoniae is the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia. We have previously identified the lipopolysaccharides (LPS) as the major adhesin of A. pleuropneumoniae involved in adherence to porcine respiratory tract cells. In the present study, adherence of A. pleuropneumoniae to porcine tracheal frozen sections was inhibited by homologous monovalent Fab fragments produced from monoclonal antibodies 5.1 G8F10 and 102-G02 directed, respectively, against the A. pleuropneumoniae serotype 1 or serotype 2 O-antigens. These results confirm the important role played by LPS in adherence of A. pleuropneumoniae and suggest that these adhesins might represent good vaccine candidates. We also investigated the presence of A. pleuropneumoniae receptors in tracheal cell preparations from piglets of four different breeds. Using Far-Western binding assays, we identified proteins recognized by whole cells of A. pleuropneumoniae reference strains for serotype 1 and 2, and local isolates belonging to the same serotypes, and also recognized by extracted LPS from both reference strains. We confirmed the proteinaceous nature of these LPS-binding molecules by their staining with Coomassie brilliant blue, sensitivity to proteinase K digestion, resistance to sodium m-periodate oxidation, and their inability to stain with glycoprotein-specific reagents. Four low-molecular-mass bands (14–17 kDa) seemed to correspond to histones. We also identified proteins at Mr 38,500 that could represent putative receptors for A. pleuropneumoniae LPS in swine respiratory tract cells. Received: 16 April 1999 / Accepted: 1 July 1999     

Drosophila spectrin. II. Conserved features of the alpha-subunit are revealed by analysis of cDNA clones and fusion proteins

Drosophila alpha-spectrin cDNA sequences were isolated from a lambda gt11 expression library. These cDNA clones encode fusion proteins that include portions of the Drosophila alpha-spectrin polypeptide as shown by a number of structural and functional criteria. The fusion proteins elicited antibodies that reacted strongly with Drosophila and vertebrate alpha-spectrins and a comparison of cyanogen bromide peptide maps demonstrated a clear structural correspondence between one fusion protein and purified Drosophila alpha-spectrin. Alpha-spectrin fusion protein also displayed calcium-dependent calmodulin-binding activity in blot overlay experiments and one fusion protein bound specifically to both Drosophila and bovine brain beta-spectrin subunits on protein blots. A region of the Drosophila cDNA cross-hybridized at lowered stringency with an avian alpha-spectrin cDNA. Together these data show that the composition, structure, and binding properties of the spectrin family of proteins have been remarkably well conserved between arthropods and vertebrates. Drosophila cDNA hybridized to an mRNA of greater than or equal to 9 kb on blots of total Drosophila poly A+ RNA; and hybridized in situ to a single site in polytene region 62B, 1-7. This result and Southern blot analysis of genomic DNA indicate that the sequences are likely to be single copy in the Drosophila genome.     

Molecular cloning of a determinant coding for fimbrial antigen F165(1), a Prs-like fimbrial antigen from porcine septicaemic Escherichia coli.

The genetic determinant coding for F165(1) fimbriae was cloned from the chromosome of the porcine Escherichia coli wild-type strain 4787 (O115:K-:H51:F165). The fimbrial determinant was further subcloned into the BamHI site of pACYC184 and a restriction map was established. On Southern hybridization, identity between the chromosomally encoded prs-like determinant of strain 4787 and its cloned counterparts was demonstrated. The cloned F165(1) fimbriae and those of the wild-type strain possessed a major protein subunit of molecular mass 18.5 kDa. Strains expressing F165(1) fimbriae were detected using an F165-specific polyclonal antiserum and caused mannose-resistant haemagglutination and agglutination of Forssman latex beads. Antiserum against the cloned F165(1) fimbriae recognized a 18.5 kDa band in the parent strain 4787.     

Escherichia coli STb toxin and colibacillosis: knowing is half the battle.

Expression of both adherence and enterotoxin expression are required for enterotoxigenic Escherichia coli (ETEC) strains to cause colibacillosis. ETEC strains are responsible for diarrhea in humans and animals by production of various enterotoxins. For many years, the role of the heat-stable E. coli enterotoxin STb as a diarrhea-causing toxin in animals, and in particular in swine, has been controversial. In fact, although the presence of STb-positive E. coli strains and diarrhea in animals is frequently observed, the difficulty of reproducing the pathology in an animal model was interpreted as a lack of toxicity. Recently, new light was shed on the activity of STb in intestinal ligated loops and in pigs orally inoculated with STb-positive E. coli strains. This minireview revisits the effects of STb on the intestinal epithelium and enlightens the significance of STb in swine colibacillosis. The interaction of STb toxin with other E. coli enterotoxins and dual ETEC/enteropathogenic E. coli or ETEC/attaching effacing E. coli infections are also discussed.