Predicting polygynous settlement while incorporating varying female competitive strength

The rationale behind the polygyny threshold model is that thebreeding situation quality (BSQ) males have to offer femalesvaries, and that differences in BSQ offset females' costs ofsharing with other females, thus favoring polygynous settling.It predicts that the first chosen territories become polygynousfirst, and that breeding success of secondary and contemporarymonogamous females is similar. This is not generally found.Testing of the polygyny threshold model (PTM) assumes that femalesare equal competitors and distribute ideally free around availablebreeding resources, a condition probably not often met. If sharinga male is costly, and competitors differ in quality, weakerindividuals should experience degrees of competitive exclusion.Setting female competitive abilities proportional to arrivalorder, we use an individual-based interference-competition modelto examine settlement patterns. Shifts in the ratio of variancein interfemale competitiveness to interterritorial differencesin BSQ result in various settlement patterns, with differentpredictions concerning settlement order and fitness returns.We find support for the novel predictions from data on northernlapwing (Vanellus vanellus), starling (Sturnus vulgaris), piedflycatcher (Ficedula hypoleuca), and blue tit (Parus caeruleus).We suggest that before testing polygyny predictions, an evaluationof the settlement sequence should be made, which may help togenerate more accurate predictions. We argue that violationof the "equal female" assumption may explain much of the discrepancybetween predictions and empirical findings in previous testsof the PTM, and that secondary females in general have lowersuccess than do monogamous breeders because they are of lowerquality.     

Covalent anthocyanin-flavone dimer from leaves of Oxalis triangularis

The anthocyanin-flavone C-glycoside, (malvidin 3-O-(6(II)-O-alpha-rhamnopyranosyl(AIV)-beta-glucopyranoside(AII))-5-O-beta-glucopyranoside(AIII)) (apigenin 6-C-(2(II)-O-beta-glucopyranosyl(FIII)-beta-glucopyranoside(FII))) malonate(AV) (A(IV)-4-->A(V)-1, F(III)-6-->A(V)-3) (1), has been isolated from leaves of Oxalis triangularis A. St.-Hil. In the 1D (1)H NMR spectrum of 1 dissolved in CD(3)OD-CF(3)CO(2)D (95:5), MTFA, recorded 45 min after sample preparation, this covalently linked dimer occurred mainly as flavylium cation (38%) and two equilibrium forms assigned to be quinonoidal bases (54%), whereas only minor amounts of the hemiacetal forms were present. After five days storage at 300 K, the hemiacetals (39%) and flavylium cation (38%) constituted the main forms of 1. More simple anthocyanins are normally considered to be on the flavylium cation form in acidified deuterated methanol. The cross-peaks observed in NOESY NMR spectra of 1 indicated the presence of vertical 'pi-pi' stacking between the B-ring of the flavone unit and the A-ring of each of the two forms assigned to be quinonoidal bases. It was not possible to discriminate between inter- or intramolecular association mechanisms. The equilibria between the various forms of 1 were studied by two-dimensional NOESY and ROESY NMR spectroscopy. 2D HSQC-TOCSY NMR spectroscopy was among the methods used for characterization of the various forms.     

Behavioral plasticity in rainbow trout (Oncorhynchus mykiss) with divergent coping styles: when doves become hawks

Consistent and heritable individual differences in reaction to challenges, often referred to as stress coping styles, have been extensively documented in vertebrates. In fish, selection for divergent post-stress plasma cortisol levels in rainbow trout (Oncorhynchus mykiss) has yielded a low (LR) and a high responsive (HR) strain. A suite of behavioural traits is associated with this physiological difference, with LR (proactive) fish feeding more rapidly after transfer to a new environment and being socially dominant over HR (reactive) fish. Following transport from the UK to Norway, a switch in behavioural profile occurred in trout from the 3rd generation; HR fish regained feeding sooner than LR fish in a novel environment and became dominant in size-matched HR–LR pairs. One year after transport, HR fish still fed sooner, but no difference in social dominance was found. Among offspring of transported fish, no differences in feeding were observed, but as in pre-transported 3rd generation fish, HR fish lost fights for social dominance against size-matched LR opponents. Transported fish and their offspring retained their distinctive physiological profile throughout the study; HR fish showed consistently higher post-stress cortisol levels at all sampling points. Altered risk-taking and social dominance immediately after transport may be explained by the fact that HR fish lost more body mass during transport than did LR fish. These data demonstrate that some behavioural components of stress coping styles can be modified by experience, whereas behavioural plasticity is limited by genetic effects determining social position early in life story.     

Exercise training corrects control of spontaneous calcium waves in hearts from myocardial infarction heart failure rats

Impaired cardiac control of intracellular diastolic Ca(2+) gives rise to arrhythmias. Whereas exercise training corrects abnormal cyclic Ca(2+) handling in heart failure, the effect on diastolic Ca(2+) remains unstudied. Here, we studied the effect of exercise training on the generation and propagation of spontaneous diastolic Ca(2+) waves in failing cardiomyocytes. Post-myocardial infarction heart failure was induced in Sprague-Dawley rats by coronary artery ligation. Echocardiography confirmed left ventricular infarctions of 40 ± 5%, whereas heart failure was indicated by increased left ventricular end-diastolic pressures, decreased contraction-relaxation rates, and pathological hypertrophy. Spontaneous Ca(2+) waves were imaged by laser linescanning confocal microscopy (488 nm excitation/505-530 nm emission) in 2 μM Fluo-3-loaded cardiomyocytes at 37°C and extracellular Ca(2+) of 1.2 and 5.0 mM. These studies showed that spontaneous Ca(2+) wave frequency was higher at 5.0 mM than 1.2 mM extracellular Ca(2+) in all rats, but failing cardiomyocytes generated 50% (P < 0.01) more waves compared to sham-operated controls at Ca(2+) 1.2 and 5.0 mM. Exercise training reduced the frequency of spontaneous waves at both 1.2 and 5.0 mM Ca(2+) (P < 0.05), although complete normalization was not achieved. Exercise training also increased the aborted/completed ratio of waves at 1.2 mM Ca(2+) (P < 0.01), but not 5.0 mM. Finally, we repeated these studies after inhibiting the nitric oxide synthase with L-NAME. No differential effects were found; thus, mediation did not involve the nitric oxide synthase. In conclusion, exercise training improved the cardiomyocyte control of diastolic Ca(2+) by reducing the Ca(2+) wave frequency and by improving the ability to abort spontaneous Ca(2+) waves after their generation, but before cell-wide propagation.     

Tissue transglutaminase-mediated formation and cleavage of histamine-gliadin complexes: biological effects and implications for celiac disease

Celiac disease is an HLA-DQ2-associated disorder characterized by an intestinal T cell response. The disease-relevant T cells secrete IFN-gamma upon recognition of gluten peptides that have been deamidated in vivo by the enzyme tissue transglutaminase (transglutaminase 2 (TG2)). The celiac intestinal mucosa contains elevated numbers of mast cells, and increased histamine secretion has been reported in celiac patients. This appears paradoxical because histamine typically biases T cell responses in the direction of Th2 instead of the Th1 pattern seen in the celiac lesions. We report that histamine is an excellent substrate for TG2, and it can be efficiently conjugated to gluten peptides through TG2-mediated transamidation. Histamine-peptide conjugates do not exert agonistic effects on histamine receptors, and scavenging of biologically active histamine by gluten peptide conjugation can have physiological implications and may contribute to the mucosal IFN-gamma response in active disease. Interestingly, TG2 is able to hydrolyze the peptide-histamine conjugates when the concentrations of substrates are lowered, thereby releasing deamidated gluten peptides that are stimulatory to T cells.     

Cholecystokinin mRNA in Atlantic herring, Clupea harengus--molecular cloning, characterization, and distribution in the digestive tract during the early life stages

The mRNA of the peptide hormone cholecystokinin (CCK) was isolated from juvenile Atlantic herring, Clupea harengus, by RT-PCR. The open reading frame encodes a 137 amino acid-long precursor protein. The peptide sequence of herring CCK-8, DYMGWMDF, is identical to that of higher vertebrates and elasmobranchs, and contains methionine in the sixth position from the C-terminus, which has not been reported previously in teleosts. Expression analysis by in situ hybridization shows that positive endocrine-like cells were mainly located in the pyloric caeca and to a less extent in the rectum of the juvenile. A few positive cells were also found in the pyloric portion of the stomach and the intestine. CCK cells were present in all the larvae examined from the day of hatching onwards. Although the CCK cells were scattered throughout the whole midgut, no signals were detected in either the foregut or the hindgut. Since herring larvae have a straight gut, the distribution pattern of CCK cells seems to be reflected in the anatomy of the gut.     

CD4dimCD25bright Treg cell frequencies above a standardized gating threshold are similar in asthmatics and controls.

BACKGROUND: Thymus selected CD4(+)CD25(bright) natural regulatory Treg cells expressing FOXP3 may contribute to control of immune responses. No unique markers have been available to identify and characterize Treg. We present a gating strategy that allows enumeration of Treg on the basis of CD4 and CD25 and investigate whether asthmatics have fewer Treg than controls. METHODS: Asthmatics and controls were selected from responses to a mailed questionnaire. CD25, CD4, HLA DR, and appropriate isotypes were recorded by flow cytometry. RESULTS: The CD4 T cells expressing most CD25 are a separate population expressing FOXP3 and lower levels of CD4 and CD127. On a CD4 CD25 dot-plot, the CD4 MFI of Treg for 152 participants was calculated to be 0.83 +/- 0.043*MFI of CD25(bright) T-cells. CD4(dim)CD25(bright) T cells in a rectangular gate with a CD4 MFI 相似文献   

The binding of 14-3-3γ to membranes studied by intrinsic fluorescence spectroscopy

Human 14-3-3 proteins contain two conserved tryptophan residues in each monomer, Trp60 and Trp233 in isoform γ. 14-3-3γ binds to negatively charged membranes and here we show that membrane binding can be monitored by steady-state intrinsic fluorescence spectroscopy. Measurements with W60F and W233F 14-3-3γ mutants revealed that Trp60 is the major contributor to the emission fluorescence, whereas the fluorescence of Trp233, which π-stacks with Tyr184, is quenched. The fluorescence is reduced and red-shifted upon specific binding of a phosphate ligand, and further red-shifted upon binding of 14-3-3γ to the membrane, compatible with solvent exposure of Trp60. Moreover, our results support that membrane binding involves the non-conserved, convex area of 14-3-3γ, and that Trp residues do not intercalate in the bilayer.