Simultaneous selection on two fitness-related traits in the butterfly Bicyclus anynana

Abstract. Theory about the role of constraints in evolution is abundant, but few empirical data exist to describe the consequences a bias in phenotypic variation has for micro evolution. Responses to natural selection can be severely hampered by a genetic correlation among a suite of traits. Constraints can be studied using antagonistic selection experiments, that is, two-trait selection in opposition to this correlation. The two traits studied here were development time and wing pattern (eyespot size) in the butterfly Bicyclus anynana , both of which have a clear adaptive significance. Rates of response were higher for eyespot size than for development time, but were independent of the concurrent selection (either in the same direction as the correlation or perpendicular to it). Regimes differed in both traits in all directions after 11 generations of selection. The uncoupling lines had higher relative responses than the synergistic lines in development time and equal relative responses in eyespot size. The patterns for eyespot size (reaction norms) were consistent across different rearing temperatures. Differences in lines selected for fast and slow development time were more pronounced at lower temperatures, irrespective of the direction of joint wing pattern selection. Furthermore, correlated responses in pupal weight and growth rate were observed; lines selected for a slower development had higher pupal weights, especially at lower temperatures. The response of the uncoupling lines was not hampered by a lack of selectable genetic variation, and the relative response in the development time was larger than expected based on response in the coupled direction and quantitative genetic predictions. This suggests that the structure of the genetic architecture does not constrain the short-term, independent evolution of both wing pattern and development time.     

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) from a false killer whale,Pseudorca crassidens (Cetacea: Delphinidae), stranded on the coast of Uruguay

Stenurus globicephalae Baylis et Daubney, 1925 (Nematoda: Pseudaliidae) was found in the cranial air sinuses of a false killer whale, Pseudorca crassidens (Owen), stranded on the coast of Uruguay in 1999. Although this species has been reported once in P. crassidens from the North Atlantic, this is the first record for South America. A total of 920 specimens were obtained, of which 663 were females (body length: 4.34 +/- 0.45 cm) and 257 were males (2.99 +/- 0.18 cm). Morphometric details are presented for S. globicephalae in this host, which do not show significant differences from those parasitizing Globicephala melas (Traill), but are distinct from those parasitizing Peponocephala electra (Gray). The host's skull revealed loss of osseous mass with the disappearance of the left zygomatic arch, and the left jaw had three osseous fenestrations in the region related to the organ of acoustic reception. These lesions support the hypothesis that this infection, known as stenurosis, was related to the stranding.     

Donor T cell activation initiates small bowel allograft rejection through an IFN-gamma-inducible protein-10-dependent mechanism

The poor success in controlling small bowel (SB) allograft rejection is partially attributed to the unique immune environment in the donor intestine. We hypothesized that Ag-induced activation of donor-derived T cells contributes to the initiation of SB allograft rejection. To address the role of donor T cell activation in SB transplantation, SB grafts from DO11.10 TCR transgenic mice (BALB/c, H-2L(d+)) were transplanted into BALB/c (isografts), or single class I MHC-mismatched (L(d)-deficient) BALB/c H-2(dm2) (dm2, H-2L(d-)) mutant mice (allografts). Graft survival was followed after injection of control or antigenic OVA(323-339) peptide. Eighty percent of SB allografts developed severe rejection in mice treated with antigenic peptide, whereas <20% of allografts were rejected in mice treated with control peptide (p < 0.05). Isografts survived >30 days regardless of OVA(323-339) administration. Activation of donor T cells increased intragraft expression of proinflammatory cytokine (IFN-gamma) and CXC chemokine IFN-gamma-inducible protein-10 mRNA and enhanced activation and accumulation of host NK and T cells in SB allografts. Treatment of mice with neutralizing anti-IFN-gamma-inducible protein-10 mAb increased SB allograft survival in Ag-treated mice (67%; p < 0.05) and reduced accumulation of host T cells and NK cells in the lamina propria but not mesenteric lymph nodes. These results suggest that activation of donor T cells after SB allotransplantation induces production of a Th1-like profile of cytokines and CXC chemokines that enhance infiltration of host T cells and NK cells in SB allografts. Blocking this pathway may be of therapeutic value in controlling SB allograft rejection.     

Antigen-antibody immune complexes empower dendritic cells to efficiently prime specific CD8+ CTL responses in vivo

Dendritic cells (DCs) require a maturation signal to acquire efficient CTL-priming capacity. In vitro FcgammaR-mediated internalization of Ag-Ab immune complexes (ICs) can induce maturation of DCs. In this study, we show that IC-induced DC maturation in vitro enables DCs to prime peptide-specific CD8+ CTLs in vivo, independently of CD4+ Th cells. Importantly, OVA/anti-OVA IC-treated DCs not only primed CD8+ CTLs to an exogenously loaded peptide nonrelated to OVA, but also efficiently primed CTLs against the dominant CTL epitope derived from the OVA Ag present in the ICs. Our studies show that ICs fulfill a dual role in priming of CD8+ CTL responses to exogenous Ags: enhancement of Ag uptake by DCs and activation of DCs, resulting in "license to kill." These findings indicate that the presence of specific Abs can crucially affect the induction of cytotoxic cellular responses.     

Effect of iron supplementation on oxidative stress and antioxidant status in iron-deficiency anemia

This study was designed to measure the effect of iron supplementation on antioxidant status in iron-deficient anemia, including the time for hemoglobin normalization and at the time of filling of iron body stores. The extent of plasma lipid peroxidation was evaluated by measuring the levels of malondialdehyde and glutathione peroxidase (GSH-Px), and the activities of superoxide dismutase (SOD) and catalase in 63 patients with iron-deficiency anemia before and after 6 wk of iron supplementation and at the time when body iron stores are saturated. After 6 wk of iron supplementation, a significant decrease of oxidative stress was observed in the treated subjects relative to controls (p<0.05). No significant differences existed between treated patients at 6 wk and at the end of the study. The erythrocyte levels of catalase, SOD, and GSH-Px were significantly lower in treated patients relative to controls (p<0.05). These levels increased after 6 wk of supplementation (p<0.05) and showed no significant differences with those at the end of the study.     

The relationship between total sialic acid levels and antioxidant status in the tadpoles of Bufo viridis and Rana ridibunda ridibunda

Total sialic acid levels (TSA), antioxidant enzymes activities such as superoxide dismutase (SOD), catalase (CAT) and lipid peroxidation (LPO) levels were investigated during the developmental period in tadpoles of the predominantly terrestrial amphibian B. viridis and the predominantly aquatic amphibian R. r. ridibunda. Maximum TSA levels were observed in B. viridis and R. r. ridibunda at the fifth and third week of their development, respectively. SOD and CAT activity variations during development in B. viridis were higher than in R. r. ridibunda. Although SOD activity in B. viridis was higher than R. r. ridibunda at the eighth week, SOD activity increased 19.2-fold in R. r. ridibunda and 10.4-fold in B. viridis between the first and eighth week. CAT activity in R. r. ridibunda did not significantly change (p>0.001) until the fifth week then increased, whereas in B. viridis CAT increased after the third week. In contrast to the rise in the antioxidant enzyme activities, LPO levels tended to decrease during the developmental period. Levels of LPO showed a similar trend until the third week for both species. The minimum LPO levels in B. viridis and R. r. ridibunda were 23+/-1.2 and 146+/-7.3 nmol MDA g(-1) tissue, at the eighth week, respectively. While decreasing LPO levels correlated with increasing antioxidant enzyme activities, TSA tended to decrease after reaching a maximum point.     

Biosynthesis of isotopically labeled gramicidins and tyrocidins by Bacillus brevis

The three-dimensional structure of bilayer-associated gramicidin A is available from a structural data base. This and related peptides are, therefore, ideal model compounds to use during the implementation and development of new NMR techniques for the structural investigations of membrane proteins. As these methods rely on the isotopic labelling of single, selected or all sites, we have, investigated and optimised biochemical protocols using different strains of the Gram-positive bacterium Bacillus brevis. With newly developed schemes for isotopic labelling large amounts of gramicidin and tyrocidin enriched with stable isotopes such as ¹⁵N or ¹⁵N/¹³C have been obtained at low cost. A variety of analytical and spectroscopic techniques, including HPLC, mass spectrometry and NMR spectroscopy are used to characterise the resulting products.     

Mycotoxins inactivation by extrusion cooking of corn flour

AIMS: To evaluate the effects of the extrusion cooking process on the inactivation of mycotoxins in corn flour. METHODS AND RESULTS: Samples of corn flour experimentally contaminated with aflatoxin B1 (AFB1) (50 ppb) and deoxynivalenol (DON) (5 ppm) were extruded. The effects of three extrusion variables (flour moisture, extrusion temperature and sodium metabisulphite addition) were analysed according to a two-level factorial design. The process was effective for the reduction of DON content (higher than 95%) under all the conditions assessed, but was only partially successful (10-25%) for the decontamination of AFB1. CONCLUSION: Extrusion cooking is effective for the inactivation of DON but is of limited value for AFB1, even if metabisulphite is added. More severe extrusion conditions are needed for the detoxification of AFB1. SIGNIFICANCE AND IMPACT OF THE STUDY: As contamination with DON occurs mainly in the field prior to harvesting and that of AFB1 is normally produced during grain storage, maize is often contaminated with DON but not with AFB1. Under these conditions, the described extrusion process can be used for the detoxification of DON. The addition of sodium metabisulphite did not significantly affect the inactivation of AFB1. Extrusion cooking is therefore an appropriate treatment for vomitoxin-contaminated maize in countries where, because of the prevailing conditions, these are the only toxins present.