Zero-knowledge cooperation in dilemma games

We consider a very simple adaptive rule that induces cooperative behavior in a large class of dilemma games. The rule has a Pavlovian flavor and can be described as win-continue, lose-reverse. It assumes no knowledge about the underlying structure of the environment (the "rules of the game") and requires very little cognitive effort. Both features make it an appealing candidate for explaining the emergence of cooperative behavior in non-human species.     

Grooming relationships between breeding females and adult group members in cooperatively breeding moustached tamarins (Saguinus mystax)

Grooming is the most common form of affiliative behavior in primates that apart from hygienic and hedonistic benefits offers important social benefits for the performing individuals. This study examined grooming behavior in a cooperatively breeding primate species, characterized by single female breeding per group, polyandrous matings, dizygotic twinning, delayed offspring dispersal, and intensive helping behavior. In this system, breeding females profit from the presence of helpers but also helpers profit from staying in a group and assisting in infant care due to the accumulation of direct and indirect fitness benefits. We examined grooming relationships of breeding females with three classes of partners (breeding males, potentially breeding males, (sub)adult non-breeding offspring) during three reproductive phases (post-partum ovarian inactivity, ovarian activity, pregnancy) in two groups of wild moustached tamarins (Saguinus mystax). We investigated whether grooming can be used to regulate group size by either "pay-for-help" or "pay-to-stay" mechanisms. Grooming of breeding females with breeding males and non-breeding offspring was more intense and more balanced than with potentially breeding males, and most grooming occurred during the breeding females' pregnancies. Grooming was skewed toward more investment by the breeding females with breeding males during the phases of ovarian activity, and with potentially breeding males during pregnancies. Our results suggest that grooming might be a mechanism used by female moustached tamarins to induce mate association with the breeding male, and to induce certain individuals to stay in the group and help with infant care.     

Mass spectrometric identification of serum peptides employing derivatized poly(glycidyl methacrylate/divinyl benzene) particles and mu-HPLC

Biomarkers play a key role in preclinical screening and diagnosis of a disease. Various support materials are utilized for this task, in combination with MALDI-TOF-MS. The way to effectively bind serum contents and their profiling is well-elaborated by the material-enhanced laser desorption ionization (MELDI) approach. In this particular work, focus is placed on the development of a strategy to identify low molecular weight serum peptides. Poly(GMA/DVB) is derivatized in a way to achieve an affinity termed as immobilized metal ion affinity chromatography (IMAC). Iminodiacetic acid (IDA) is used as a chelating ligand, whereas copper (Cu2+) acts as a metal ion for complexing peptides and proteins out of blood serum. Polymer binds the serum compounds over a broad mass range, which includes low mass peptides and high mass albumin (66 kDa). Bound contents are eluted from material by an acetonitrile/trifluoroacetic acid mixture, which proves the reversible nature of metal and amino acid linkage. Polystyrene/divinyl benzene (PS/DVB) monolithic capillary column is used for fractionation through RP-HPLC, prior to the target spotting. The tandem TOF fragment ion mass spectra of each fraction is acquired and used to search against the Swiss-Prot database, using the Mascot search engine for the identification of peptides.     

Quantification of sugar phosphate intermediates of the pentose phosphate pathway by LC-MS/MS: application to two new inherited defects of metabolism

We describe a liquid chromatography tandem mass spectrometry (LC-MS/MS) method to quantify pentose phosphate pathway intermediates (triose-3-phosphates, tetrose-4-phosphate, pentose-5-phosphate, pentulose-5-phosphates, hexose-6-phosphates and sedoheptulose-7-phosphate (sed-7P)) in bloodspots, fibroblasts and lymphoblasts. Liquid chromatography was performed using an ion pair loaded C(18) HPLC column and detection of the sugar phosphates was carried out by tandem mass spectrometry using an electron ion spray source operating in the negative mode and multiple reaction monitoring. Reference values for the pentose phosphate pathway intermediates in blood spots, fibroblasts and lymphoblasts were established. The method was applied to cells from patients affected with a deficiency of transaldolase. The transaldolase-deficient cells showed an increased concentration of sedoheptulose-7-phosphate. (Bloodspots: 5.19 and 5.43 micromol/L [0.49-3.33 micromol/L]; fibroblasts 7.43 and 26.46 micromol/mg protein [0.31-1.14 micromol/mg protein]; lymphoblasts 16.03 micromol/mg protein [0.61-2.09 micromol/mg protein].) The method was also applied to study enzymes of the pentose phosphate pathway by incubating fibroblasts or lymphoblasts homogenates with ribose-5-phosphate or 6-phosphogluconate and the subsequent analysis of the formed sugar phosphates.     

Endotoxin Inactivation in Water by Using Medium-Pressure UV Lamps

Deionized water was spiked with various concentrations of endotoxin and exposed to UV irradiation from medium-pressure UV lamps to assess endotoxin inactivation. It was found that endotoxin inactivation was proportional to the UV dose under the conditions examined. The inactivation rate was determined to be ~0.55 endotoxin unit/ml per mJ/cm² of irradiation delivered.     

New subgroups in the human T cell rearranging V gamma gene locus.

Two new V gamma genes in humans are described from rearrangement in T cell lines, which constitute single members of new V gene subgroups of the T-cell rearranging gamma (TRG gamma) locus. These two genes (herein designated as belonging to V gamma III and V gamma IV subgroups) are located between V gamma I/V gamma II subgroups and the constant (C) gamma genes. The existence of these new genes brings the number of different, potentially useable, human TRG V gamma genes to eight (excluding at least five pseudo V gamma genes) and the number of distinct subgroups to four. Polymorphism in the sequence of the V gamma II subgroup gene is also described and rearranged fragment sizes which make possible an unequivocal assignment of a V gamma rearrangement are given. These results extend previous conclusions of the inherited diversity of the human TRG V gamma locus.     

A gamma 3 hinge region probe: first specific human immunoglobulin subclass probe

We report the first specific human immunoglobulin subclass probe which was obtained by subcloning the gamma 3 hinge region. This specific gamma 3 probe allowed us to identify with certainty the C gamma 3 gene on Southern genomic blots, to describe the first C gamma 3 restriction fragment length polymorphism (EZZ gamma 3 RF) and to show that an IgG3 selective deficiency, previously described serologically, was not due to a deletion of the C gamma 3 gene. Such a probe should be particularly useful for screening libraries from individuals with IgG3 immunodeficiencies or presenting unusual C gamma 3 genes and, consequently, for studying the C gamma gene evolution.