Identification of chicken lysozyme <Emphasis Type="Italic">g</Emphasis>2 and its expression in the intestine

Lysozyme is an important component of the innate immune system, protecting the gastrointestinal tract from infection. The aim of the present study was to determine if lysozyme is expressed in the chicken (Gallus gallus) intestine and to characterise the molecular forms expressed. Immunohistochemical staining localised lysozyme to epithelial cells of the villous epithelium along the length of the small intestine. There was no evidence for lysozyme expression in crypt epithelium and no evidence for Paneth cells. Immunoblots of chicken intestinal protein revealed three proteins: a 14-kDa band consistent with lysozyme c, and two additional bands of approximately 21 and 23 kDa, the latter consistent with lysozyme g. RT-PCR analyses confirmed that lysozyme c mRNA is expressed in 4-day, but not older chicken intestine and lysozyme g in 4- to 35-day chicken intestine. A novel chicken lysozyme g2 gene was identified by in silico analyses and mRNA for this lysozyme g2 was identified in the intestine from chickens of all ages. Chicken lysozyme g2 shows similarity with fish lysozyme g, including the absence of a signal peptide and cysteines involved in disulphide bond formation of the mammalian and bird lysozyme g proteins. Analyses using SecretomeP predict that chicken lysozyme g2 may be secreted by the non-classical secretory pathway. We conclude that lysozyme is expressed in the chicken small intestine by villous enterocytes. Lysozyme c, lysozyme g and g2 may fulfil complimentary roles in protecting the intestine.Received 4 August 2004; received after revision 1 September 2004; accepted 7 September 2004     

Fracture surface energy of the Punchbowl fault, San Andreas system

Fracture energy is a form of latent heat required to create an earthquake rupture surface and is related to parameters governing rupture propagation and processes of slip weakening. Fracture energy has been estimated from seismological and experimental rock deformation data, yet its magnitude, mechanisms of rupture surface formation and processes leading to slip weakening are not well defined. Here we quantify structural observations of the Punchbowl fault, a large-displacement exhumed fault in the San Andreas fault system, and show that the energy required to create the fracture surface area in the fault is about 300 times greater than seismological estimates would predict for a single large earthquake. If fracture energy is attributed entirely to the production of fracture surfaces, then all of the fracture surface area in the Punchbowl fault could have been produced by earthquake displacements totalling <1 km. But this would only account for a small fraction of the total energy budget, and therefore additional processes probably contributed to slip weakening during earthquake rupture.     

A splicing mutation affecting expression of ataxia-telangiectasia and Rad3-related protein (ATR) results in Seckel syndrome

Seckel syndrome (OMIM 210600) is an autosomal recessive disorder characterized by intrauterine growth retardation, dwarfism, microcephaly and mental retardation. Clinically, Seckel syndrome shares features in common with disorders involving impaired DNA-damage responses, such as Nijmegen breakage syndrome (OMIM 251260) and LIG4 syndrome (OMIM 606593). We previously mapped a locus associated with Seckel syndrome to chromosome 3q22.1-q24 in two consanguineous Pakistani families. Further marker analysis in the families, including a recently born unaffected child with a recombination in the critical region, narrowed the region to an interval of 5 Mbp between markers D3S1316 and D3S1557 (145.29 Mbp and 150.37 Mbp). The gene encoding ataxia-telangiectasia and Rad3-related protein (ATR) maps to this region. A fibroblast cell line derived from an affected individual displays a defective DNA damage response caused by impaired ATR function. We identified a synonymous mutation in affected individuals that alters ATR splicing. The mutation confers a phenotype including marked microcephaly (head circumference 12 s.d. below the mean) and dwarfism (5 s.d. below the mean). Our analysis shows that UV-induced ATR activation can occur in non-replicating cells following processing by nucleotide excision repair.     

Efficiency of anthracene as a suspended scintillator for counting aqueous nickel-63 samples

Zusammenfassung Die Zählausbeute einer Anthrazenkristallsuspension als Szintillatormaterial wurde für die Betastrahlung des Ni-63-Isotops untersucht. Die Methode ist eine anpassungsfähige Ergänzung zur bekannten Flüssigkeitsszintillationsmessung.

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The authors are grateful to Dr.J. D. Punch of Medical College of Virginia for the use of his liquid scintillation spectrometer.     

Egalitarian motives in humans

Participants in laboratory games are often willing to alter others' incomes at a cost to themselves, and this behaviour has the effect of promoting cooperation. What motivates this action is unclear: punishment and reward aimed at promoting cooperation cannot be distinguished from attempts to produce equality. To understand costly taking and costly giving, we create an experimental game that isolates egalitarian motives. The results show that subjects reduce and augment others' incomes, at a personal cost, even when there is no cooperative behaviour to be reinforced. Furthermore, the size and frequency of income alterations are strongly influenced by inequality. Emotions towards top earners become increasingly negative as inequality increases, and those who express these emotions spend more to reduce above-average earners' incomes and to increase below-average earners' incomes. The results suggest that egalitarian motives affect income-altering behaviours, and may therefore be an important factor underlying the evolution of strong reciprocity and, hence, cooperation in humans.