Heteroclitic recognition of combinatorial TX1TX2T peptide mixtures by mucin-2 protein specific monoclonal antibody.

The mucin-2 (MUC2) glycoprotein secreted by the epithelial cells of human colon may be abnormally under-glycosylated in the case of cancer. Monoclonal antibody (mAb) 994 raised against the immunogenic part of the protein core, recognizes malignant human colon tissues as well as pentapeptides with TX1TX2T motif present in MUC2. Using a combinatorial approach and ELISA experiments it was found that mAb 994 is able to recognize peptides of the sub-library TQTX2T very strongly, and to some extent also peptides from TETX2T, TLTX2T and TVTX2T sub-libraries. Binding studies with peptides corresponding to the TQTX2T and TETX2T sub-libraries showed that mAb 994 recognized only six peptides (IC50 = 9-208 micromol dm(-3)) from the 19 compounds of the TQTX2T sub-library and only three peptides (IC50 = 3500-16700 micromol dm(-3)) from the 'second-best' TETX2T sub-library. The most pronounced mAb binding occurred when Gln was in position X1 and it was much weaker in the case of Glu, Val or Leu. As for X2 amino acids, the presence of Pro, Ala can provide a strong, while Tyr, Trp, Phe and Ser a weaker, peptide-antibody interaction. Data from this study suggest that pentapeptide TQTPT, whose sequence is present in the native protein, is bound most strongly. However, almost identical binding properties were observed with peptide TQTAT, whose sequence is not present in the protein. Apart from this, some other 'heteroclitic' peptides were found with a different rank in the binding-hierarchy. Based on these peptides artificial compounds can be prepared as potential candidates for vaccine development. Results of this study also provide a rationale for understanding the molecular background of the heteroclitic nature of the MUC2 protein core specific mAb 994.     

Achillicin,the first proazulene from Achillea millefolium

Achillicin, the major proazulene (prochamazulene) of Achillea millefolium L. ssp. collina Becker has been isolated and identified as 8-acetoxyartabsin. It is the first proazulene reported for the genus Achillea and has not been found previously in plants.     

Characterisation of mutations in GroES that allow GroEL to function as a single ring

The chaperonin GroEL contains two seven-subunit rings, and allosteric signals between them are required to complete the GroEL reaction cycle. For this reason SR1, a mutant of GroEL that forms only single rings, cannot function as a chaperone. Mutations in SR1 that restore chaperone function weaken its interaction with the cochaperonin GroES. We predicted that GroES mutants with reduced affinity for GroEL would also restore function to SR1. To test this, we mutated residues in GroES in and near its contact site with GroEL. Nearly half of the mutants showed partial function with SR1. Two mutants were confirmed to have reduced affinity for GroEL. Intriguingly, some GroES mutants were able to function with active single ring mutants of GroEL.     

Corticosterone,Avoidance of Novelty,Risk‐Taking and Aggression in a Wild Bird: No Evidence for Pleiotropic Effects

Certain inherent characteristics of individuals can determine both physiological and behavioural responses to environmental challenges, which could drive a correlation between levels of corticosterone (CORT), the most important stress hormone and behavioural profiles. Therefore, CORT level may mediate consistent behaviours along the shy/bold continuum, and thus, it could serve as a pleiotropic basis for behavioural syndromes. Moreover, behavioural responses to environmental challenges may have consequences for CORT concentrations, which would also result in a correlation between physiology and behaviours even without requiring pleiotropic mechanisms. Accordingly, we investigated the relationship between CORT and behaviour in free‐living male collared flycatchers, Ficedula albicollis, using recently developed field assays. More specifically, we characterised novel object avoidance, intraspecific aggression and risk‐taking in males and related these correlated behaviours to the concentration of CORT metabolites in droppings measured by enzyme immunoassay. Individuals with higher levels of excreted CORT metabolites had no consistently higher or lower behavioural scores along the shy/bold spectrum, as avoidance of novelty, aggression and risk‐taking were not systematically related to CORT metabolite concentrations in the same direction. Moreover, environmental challenges owing to the presence of a novel object, territorial intruder and a potential predator caused no elevation in the level of CORT metabolites. Therefore, we did not find correlative evidence for CORT driving correlated behaviours through pleiotropic effects or for particular behaviours during courtship causing elevation in CORT levels.     

An aggregation attractant for the sugar-beet weevil, Bothynoderes punctiventris

During our screening studies, attractiveness of a ternary mixture of synthetic Grandlure I [racemic cis‐1‐methyl‐2‐(1‐methylenethenyl)‐cyclobutane ethanol], Grandlure II [(Z)‐2‐(3,3‐dimethyl)cyclohexylidene ethanol], and Grandlure III–IV [(Z)‐ and (E)‐2‐ochtodenal; (Z)‐ and (E)‐(3,3‐dimethyl)cyclohexylidene acetaldehyde] for the sugar‐beet weevil, Bothynoderes punctiventris Germar (Coleoptera: Curculionidae), was observed in field‐trapping tests at several sites in Hungary and Serbia. The mixture attracted both males and females. Later tests revealed that of the components in the ternary mixture, only Grandlure III–IV were responsible for attraction, and the addition of Grandlures I or II in varying percentages had no influence on trap captures. Traps baited with 50–50 000 µg of Grandlure III–IV on rubber or polyethylene dispensers yielded high catches of weevils. When testing synthetic samples enriched in the respective geometrical isomer, Grandlure IV had a tendency of catching more weevils, but differences were not significant from lower catches by a 1:1 Z:E blend or Grandlure III. In gas chromatography–flame ionization detection/electroantennographic detection studies, antennae of both female and male weevils were more responsive to the (E)‐ than to the (Z)‐isomer suggesting a more important role for Grandlure IV. Efforts to verify the presence of Grandlure III or IV in volatiles collected from either sex of live sugar‐beet weevils or body washings with pentane remained inconclusive. Traps baited with Grandlure III–IV can now be used as sensitive and powerful trapping tools in the control of the sugar‐beet weevil.