Reproductives and eggs trigger worker vibration in a subterranean termite

In insect societies, the presence of reproductives or eggs has been shown to shape several biological traits in the colony members. Social interactions are one of these traits that involve modification of the communication system of the entire colony. Many studies described the role of chemical compounds and dominance behaviors in the presence of reproductive but vibratory behaviors received very few investigations. Yet, vibratory behaviors are ideal candidates, particularly for subterranean species like termites, as they could be quickly transmitted through the substrate and could be very diversified (origin, modulation). Here, we investigated whether the presence of reproductives/eggs affects the vibratory behavior (body‐shaking) of workers in the subterranean termite Reticulitermes flavipes. Our results reveal that the presence of reproductives or eggs triggers an increase of workers' body‐shaking, independent of their colony of origin after 24 hr. We hypothesize that vibratory communication could be used to transfer information about the presence of reproductives and eggs to the entire colony, suggesting that vibratory behaviors could serve as an important yet neglected mediator of social regulation.     

Peptide mapping of β-casein by capillary zone electrophoresis

A method to the study of -casein proteolysis by aspartic proteinases is developed. The 3% trichloroacetic acid-soluble peptides of -casein digested with cardosin A were separated by capillary zone electrophoresis under different experimental conditions in an uncoated fused silica capillary. The best separation was at pH 3.01, 30 kV and 30 °C.     

Capillary electrophoresis of caseino-peptides: influence of applied voltage and column temperature

The peptides formed upon action of purified cardoon rennet on the Ala₁₈₉-Phe₁₉₀-Leu₁₉₁-Leu₁₉₂-Tyr₁93 -casein fragment were separated by capillary electrophoresis in an uncoated fused silica capillary. There was a linear correlation between electrophoretic mobility and Z/M^2/3 (Z, net charge; M, molecular mass) under all experimental conditions tested; under the optimal condicitions, 25 kV and 40 °C, the correlation coefficient was 0.994. The reported method is fast (migration times less than 7 min) and may be used to study the action of aspartic proteinases on the C-terminal domain of -casein and thus to help elucidate their effect on cheese quality.     

Selection and Characterization of the Choline Transport Mutation Suppressor from Torpedo Electric Lobe,CTL1

The presumptive choline transporter, CTL1, was initially identified through functional complementation of a triple yeast mutant (ctr ise URA3) with deficiencies in both choline transport and choline neosynthesis under selective conditions that cause perturbations in membrane synthesis and growth. After transformation of these yeasts with a heterologous yeast expression library made from Torpedo electric lobe cDNAs, several colonies showed increased growth but only one clone increased the accumulation of external choline. The corresponding full-length cDNA was isolated and encodes a protein with 10 transmembrane domains. Northern analysis of Torpedo mRNA indicates that CTL1 is expressed at high levels in the spinal cord and brain. In Xenopus oocytes, Torpedo CTL1 expression was associated with the appearance of sodium independent high-affinity choline uptake. We propose that CTL1 plays a role in providing choline for membrane synthesis in the nervous system.     

Improvement of porphyrin cellular delivery and activity by conjugation to a carrier peptide

The chemical nuclease metalloporphyrin (manganese(III) porphyrin) can cleave DNA irreversibly and can thus constitute a potential antitumor drug. However, these molecules show low permeability to cell surface membranes. We report here the conjugation of an amphipathic carrier peptide to improve considerably its cellular delivery. The metalloporphyrin-peptide conjugate can be internalized by cells within only 5 min of incubation with a yield as high as 80%. Furthermore, the metalloporphyrin-peptide conjugate is able to cleave in vitro high or low molecular weight DNA to the same extend as metalloporphyrin alone without affecting the sequence-specific cleaving activity of the porphyrin. The conjugate is 100-fold more efficient at inducing tumor cells death than the free metalloporphyrin via a mechanism involving genomic DNA cleavage. The results are promising for further therapeutic applications with antitumor drugs such as metalloporphyrin, and also with other existing drugs by using a carrier peptide system in order to improve the cellular uptake of such molecules.     

Synthesis,radiolabeling and preliminary biological evaluation of radiolabeled 5-methyl-6-nitroquipazine,a potential radioligand for the serotonin transporter

5-Methyl-6-nitroquipazine, a novel analogue of the potent and selective serotonin transporter inhibitor 6-nitroquipazine was synthesized and radiolabeled with tritium and the positron emitter carbon-11. [³H]5-methyl-6-nitroquipazine was found to have a K_d=51±7 pM. The high affinity and the facile labeling of [¹¹C]5-methyl-6-nitroquipazine makes it a promising radioligand for visualization of the serotonin transporter with positron emission tomography.     

Nonperturbing fluorescent labeling of polysaccharides

A fluorescent labeling procedure, which does not perturb macromolecular conformations, was employed to bind a rhodamine derivative to the reducing end of several water-soluble polysaccharides by reductive amination in the presence of sodium cyanoborohydride. Fluorescence correlation spectroscopy, atomic force microscopy, and size exclusion chromatography were used to demonstrate that the conformations of the polysaccharides schizophyllan, polygalacturonic acid (PGUA), succinoglycan, and several dextrans were maintained following the labeling procedure.     

Attaching histidine-tagged peptides and proteins to lipid-based carriers through use of metal-ion-chelating lipids

The therapeutic potential of selected peptides and proteins is enormous, with applications ranging from use as therapeutic vaccines, as modulators of intracellular signaling pathways and as highly selective agents capable of recognizing unique extracellular targets. We have been pursuing development of hybrid lipid-based carrier formulations designed to take advantage of the therapeutic benefits of peptides selected for their ability to act in a complementary fashion with the carrier system. In this regard, it is critical to have simple and versatile methods to promote and control the binding of diverse peptides to a broad range of carrier formulations. As demonstrated here, recombinant proteins and synthetic peptides containing poly-histidine residues (4 to 10) can be specifically bound to liposomes containing a metal-ion-chelating lipid, DOGS-NTA-Ni. The potential of this approach is demonstrated using two functional peptides, AntpHD-Cw3 (applications for vaccine production) and AHNP (specificity for Her-2 expressing cells).