Ecological and social determinants of association and proximity patterns in the fission–fusion society of spider monkeys (Ateles geoffroyi)

Some social species exhibit high levels of fission–fusion dynamics (FFD) that improve foraging efficiency. In this study, we shed light on the way that FFD allows animal groups to cope with fluctuations in fruit availability. We explore the relative contribution of fruit availability and social factors like sex in determining association and proximity patterns in spider monkeys. We tested the influence of fruit availability and social factors on the association and proximity patterns using three-year data from a group of spider monkeys in the Yucatan Peninsula of Mexico. We identified subgroup members and estimated their Interindividual distances through instantaneous scan sampling. We evaluated fruit availability by monitoring the phenology of the 10 most important food tree species for spider monkeys in the study site. Social network analyses allowed us to evaluate association and proximity patterns in subgroups. We showed that association patterns vary between seasons, respond to changes in fruit availability, and are influenced by the sex of individuals, likely reflecting biological and behavioral differences between sexes and the interplay between ecological and social factors. In contrast, proximity patterns were minimally affected by changes in fruit availability, suggesting that social factors are more important than food availability in determining cohesion within subgroups.     

The reproductive biology of the Rock Partridge Alectoris graeca saxatilis in the southern French Alps: first evidence of double-nesting behaviour

Capsule: Double-nesting occurs frequently in Rock Partridges Alectoris graeca living in the southern French Alps.

Aims: To investigate reproductive parameters of a Rock Partridge Alectoris graeca population.

Methods: The reproductive behaviour of 62 radio-tagged birds was monitored during the breeding seasons 2012–16, to record breeding phenology, clutch sizes, hatching success, nest survival and parental care.

Results: Double-nesting behaviour in the Rock Partridge was confirmed for the first time. Participation in incubation was similar for males and females (86% versus 70%). Clutch size was larger for nests incubated by males (11.0?±?1.6 eggs) than by females (9.5?±?1.2). Male nest survival rate (0.37) tended to be lower than female nest survival rate (0.62), although the difference was not significant. No significant difference was detected between male and female hatching success. Nest failures were caused by mammals taking the eggs (78%) or predation of the incubating parent (13%). Some circumstantial evidence suggests that occurrence of double-nesting behaviour could depend on previous winter and spring weather influencing the body condition of females. The reproductive biology of the Rock Partridge contrasts in some breeding traits with Red-legged Partridge and natural partridge hybrids, possibly due to climatic differences between habitats.

Conclusion: Confirmation of double-nesting in Rock Partridges indicates that climatic constraints inherent to its mountain environment do not act as an impediment to this behaviour. Variation in weather conditions between years could influence the annual occurrence of double-nesting.     

A compatible interaction of Alternaria brassicicola with Arabidopsis thaliana ecotype DiG: evidence for a specific transcriptional signature

Background  

The interaction of Arabidopsis with Alternaria brassicicola provides a model for disease caused by necrotrophs, but a drawback has been the lack of a compatible pathosystem. Infection of most ecotypes, including the widely-studied line Col-0, with this pathogen generally leads to a lesion that does not expand beyond the inoculated area. This study examines an ecotype, Dijon G (DiG), which is considered sensitive to A. brassicicola.     

Maturation and persistence of the anti-SARS-CoV-2 memory B cell response

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Induction, by adriamycin and mitomycin C, of modifications in lipid composition, size distribution, membrane fluidity and permeability of cultured RDM4 lymphoma cells

Adriamycin and mitomycin C were previously found to modulate the sensitivity of lymphoma cells to lysis by certain effectors of immunity and this modulation was dependent on drug concentration. In the present studies, RDM4 lymphoma cells were treated with different concentrations of the two drugs for 24 h in culture. These treatments resulted in changes in the lipid composition, membrane fluidity, cell size distribution, and permeability to 51CrO4, Trypan blue, Acridine orange and trimethylaminodiphenylhexatriene (TMA-DPH) of the cells. Changes in some of these parameters, as a function of drug concentration, resulted in dose-response curves which were bell-like shaped, hence paradoxical similarities between non-drug-treated cells and cells treated with higher drug concentrations were observed.     

Hyperexpression of recombinant CFTR in heterologous cells alters its physiological properties

We investigated whether high levels of expression of the cysticfibrosis transmembrane conductance regulator (CFTR) would alter thefunctional properties of newly synthesized recombinant proteins. COS-7,CFPAC-1, and A549 cells were intranuclearly injected with a Simianvirus 40-driven pECE-CFTR plasmid and assayed for halide permeabilityusing the6-methoxy-N-(3-sulfopropyl)quinolinium fluorescent probe. With increasing numbers of microinjected pECE-CFTR copies, the baseline permeability to halide dose dependently increased, and the response to adenosine 3',5'-cyclic monophosphate(cAMP) stimulation decreased. In cells hyperexpressing CFTR, the high level of halide permeability was reduced when a cell metabolism poisoning cocktail was applied to decrease intracellular ATP and, inversely, was increased by orthovanadate. In CFPAC-1 cellsinvestigated with the patch-clamp technique, CFTR hyperexpression ledto a time-independent nonrectifying chloride current that was notsensitive to cAMP stimulation. CFPAC-1 cells hyperexpressing CFTRexhibited no outward rectifying chloride current nor inward rectifyingpotassium current either spontaneously or under cAMP stimulation. Weconclude that hyperexpression of recombinant CFTR proteins modifiestheir properties inasmuch as 1) CFTRchannels are permanently activated and not susceptible to cAMPregulation and 2) they lose their capacity to regulate heterologous ionic channels.