Aging in personal and social immunity: do immune traits senesce at the same rate?

How much should an individual invest in immunity as it grows older? Immunity is costly and its value is likely to change across an organism's lifespan. A limited number of studies have focused on how personal immune investment changes with age in insects, but we do not know how social immunity, immune responses that protect kin, changes across lifespan, or how resources are divided between these two arms of the immune response. In this study, both personal and social immune functions are considered in the burying beetle, Nicrophorus vespilloides. We show that personal immune function declines (phenoloxidase levels) or is maintained (defensin expression) across lifespan in nonbreeding beetles but is maintained (phenoloxidase levels) or even upregulated (defensin expression) in breeding individuals. In contrast, social immunity increases in breeding burying beetles up to middle age, before decreasing in old age. Social immunity is not affected by a wounding challenge across lifespan, whereas personal immunity, through PO, is upregulated following wounding to a similar extent across lifespan. Personal immune function may be prioritized in younger individuals in order to ensure survival until reproductive maturity. If not breeding, this may then drop off in later life as state declines. As burying beetles are ephemeral breeders, breeding opportunities in later life may be rare. When allowed to breed, beetles may therefore invest heavily in “staying alive” in order to complete what could potentially be their final reproductive opportunity. As parental care is important for the survival and growth of offspring in this genus, staying alive to provide care behaviors will clearly have fitness payoffs. This study shows that all immune traits do not senesce at the same rate. In fact, the patterns observed depend upon the immune traits measured and the breeding status of the individual.     

“First experience with JenaValve?: a single-centre cohort”

Aims

Since the introduction of transcatheter aortic valve implantation (TAVI), newer generation and novel devices such as the retrievable JenaValve™ have been developed. We evaluated the procedural and 6-month results of our first experience with implantation of the JenaValve™.

Methods and results

From June 2012 to December 2013, 24 consecutive patients (mean age 80 ± 7 years, 42 % male) underwent an elective transapical TAVI with the JenaValve™. Device success was 88 %. The mortality rate was 4 % at 30 days and 31 % at 6 months. TAVI reduced the mean transvalvular gradient (44.2 ± 11.1 mmHg vs. 12.3 ± 4.3 mmHg, p < 0.001) and increased the mean aortic valve area (0.8 3 ± 0.23 to 1.70 ± 0.44 cm²). A mild paravalvular leakage (PVL) occurred in 4 patients (18 %) and a moderate PVL in 1 patient (4 %). Mean New York Heart Association Functional Class improved from 2.9 ± 0.5 to 2.0 ± 0.8 at 30 days.

Conclusion

TAVI using the JenaValve™ prosthesis seems adequate and safe in this first experience cohort.     

First pairing in Snow Geese Anser caerulescens: at what age and at what time of year does it occur?

In migratory birds, the place and time of pair formation are important parameters for population structure and dynamics. Geese are not only migratory but also exhibit long-term monogamy, and therefore the first pairing event in a bird's lifetime is of particular importance. Through behavioural observations of young, known-age, marked birds conducted on the wintering grounds during three winter seasons we investigated two aspects of the timing of first pair formation in the Wrangel Island population of Snow Geese Anser caerulescens : (1) the age at which birds first form pair bonds, and (2) the seasonal pattern of first pair formation. Wrangel Island Snow Geese paired considerably later in life than Snow Geese from a low-Arctic population: almost none of the birds formed pairs in their second winter, and many were still in sibling groups for at least part of that season. The proportion of birds in pairs continued to increase until at least 5 years of age. Most pairing took place during the observation periods, and in general the proportion of birds in pair bonds increased gradually throughout the winter season. The amount of pairing during spring migration or summer varied annually and among cohorts, indicating that even very young birds may be able to form pair bonds quickly if conditions on the breeding grounds are unusually favourable. Pairing later and remaining in family groups longer may be a response to breeding conditions in this high-Arctic colony. Here, productivity is typically low due to harsh weather and predation, whereas Snow Geese breeding in the low Arctic are less restricted and form pairs and start to breed when younger. The fact that most, but not all, pairing takes place on the wintering grounds helps explain why a previous study found a certain amount of gene flow between the two Wrangel Island subpopulations with separate wintering grounds.     

Metabolic flexibility: the key to long-term evolutionary success in Bryozoa?

Oxygen consumption (MO2) and activity were evaluated in Antarctic Bryozoa. Three species representing two different morphologies, flat sheet, laminar forms, Isoseculiflustra tenuis and Kymella polaris, and the bush form Camptoplites bicornis were used. In Bryozoa, activity is measured as the proportion of colony zooids with their lophophores extended. In I. tenuis and K. polaris, residual analysis showed that the percentage of zooids with extended lophophores was not correlated with colony MO2. Lophophore extension is, therefore, a poor measure of activity, and other costs (e.g. growth, reproduction, storage) probably form the major metabolic costs. MO2 per unit of ash-free dry mass (AFDM) in the laminar forms was low compared with other Antarctic marine invertebrates, but not lower than brachiopods and echinoderms. However, the lowest rate here, 16.8 microg O2 g AFDM(-1) h(-1) for a K. polaris colony, is (to our knowledge) the lowest for any animal so far reported. MO2 per unit of AFDM for C. bicornis, however, is among the highest reported for sessile or slow moving Antarctic marine ectotherms, with values similar to those for bivalve and gastropod molluscs. The highest rate, 527 microg O2 g AFDM(-1) h(-1) for one colony is (to our knowledge) the highest reported for polar animals of this type. Extreme diversity in metabolic strategy may explain the bryozoan long evolutionary record and great success in shallow marine environments worldwide.     

Dairy cattle exploratory and social behaviors: is there an effect of cloning?

While an increasing number of animals are produced by means of somatic cloning, behavioral studies on cloned animals are still rare. The aim of this study was to investigate whether the somatic cloning procedure has an influence on locomotion, exploratory, vocal and social behaviors of heifers. Ten heifers were used in the present study. Five of them were cloned heifers derived from somatic cells of three different Prim'Holstein cows and five others were same-age control heifers produced by artificial insemination. In addition to observations of social behaviors in the stable group, each animal was placed individually for a short time in an unfamiliar environment. Our results failed to show any statistical differences between clones and their controls both in frequencies of agonistic and non-agonistic behaviors. However, cloned heifers showed significantly more non-agonistic and less agonistic behaviors towards other cloned partners than towards control ones. This result also stood for control heifers. As far as their Hierarchical Index was concerned, three cloned heifers were highest ranking and two others lowest ranking. In this herd, social dominance appeared to be linked to body weight and age rather than to a cloning effect. In an unfamiliar environment, cloned and control subjects exhibited the same level of locomotion and vocalization. However, cloned heifers showed more exploratory behaviors than did control ones. This difference could be due to environmental factors during the postnatal period rather than to cloning.     

Feedback between zebra mussel selective feeding and algal composition affects mussel condition: did the regime changer pay a price for its success?

1. We investigated the role of algal composition on pumping, clearance, assimilation, pseudofaeces and faeces production, feeding time budgets, and condition of zebra mussels from spring to autumn at two sites in Saginaw Bay (Lake Huron) and one site in western Lake Erie. Size‐fractioned chlorophyll was used to distinguish between feeding on small (<53 μm) and large (>53 μm) size fractions, and mussel feeding behaviour was quantified by video observations. 2. Mussel pumping, clearance and assimilation rates varied among sites, particularly during summer, when phytoplankton composition varied considerably among sites. Lowest values were seen at the inner‐bay site of Saginaw Bay, low to moderate values at the outer‐bay site of Saginaw Bay, and high values at the Lake Erie site. Clearance, pumping and assimilation rates were all highly positively correlated (R² = 0.76) with per cent contribution of flagellates to total algal biomass and negatively correlated with per cent of Microcystis aeruginosa (R² = 0.63). The negative effects on pumping rate (as determined by clearance rate on the <53 μm fraction) of Microcystis, which occurred in the >53 μm fraction, could be mitigated by the presence of flagellates in the <53 μm fraction. 3. Visual observations of mussel feeding showed evidence for poor seston quality during summer negatively affecting feeding rates. High faeces production during times of low assimilation rate was suggestive of poor assimilation efficiency and/or viable gut passage of grazing resistant algae. Long periods of time not filtering by the mussels during some Microcystis blooms and lack of production of a filtering current during one experiment were suggestive of intoxication from microcystin or other secondary compounds. 4. Clearance and feeding rates of the mussels in Saginaw Bay were high during spring and autumn and very low in summer, particularly at the inner‐bay site. Condition of the mussels (mass : length ratio) was highest in spring and lowest during summer. This seasonal variation probably reflected high food assimilation rate during autumn and spring and low assimilation rate and reproduction during summer. The condition of mussels throughout the year was higher at the outer‐bay than the inner‐bay site, reflecting better feeding conditions at the former. Mussel selective feeding may have been responsible for the poor quality of food at the inner bay site; therefore, we postulate that a regime shift in phytoplankton composition promoted by the mussels fed back into lowered condition of the mussels.     

The product environmental footprint communication at the crossroad: integration into or co-existence with the European Ecolabel?

The International Journal of Life Cycle Assessment - Since 2013, the European Commission (EC) is developing and testing the Product Environmental Footprint (PEF)—a product evaluation method,...     

Begomoviruses: what is the secret(s) of their success?

Begomoviruses constitute an extremely successful group of emerging plant viruses transmitted by whiteflies of the Bemisia tabaci complex. Hosts include important vegetable, root, and fiber crops grown in the tropics and subtropics. Factors contributing to the ever-increasing diversity and success of begomoviruses include their predisposition to recombine their genomes, interaction with DNA satellites recruited throughout their evolution, presence of wild plants as a virus reservoir and a source of speciation, and extreme polyphagia and continuous movement of the insect vectors to temperate regions. These features as well as some controversial issues (replication in the insect vector, putative seed transmission, transmission by insects other than B. tabaci, and expansion of the host range to monocotyledonous plants) will be analyzed in this review.     

The interference of flexible working times with the utility of time: a predictor of social impairment?

Periodic components inherent in actual schedules of flexible working hours and their interference with social rhythms were measured using spectrum analysis. The resulting indicators of periodicity and interference were then related to the reported social impairments of workers. The results show that a suppression of the 24 and the 168 h (seven-day) components (absence of periodicity) in the work schedules predicts reported social impairment. However, even if there are relatively strong 24 and 168 h components left in the work schedules, their interference with the social rhythm (using the phase difference between working hours and the utility of time) further predicts impairment. The results thus indicate that the periodicity of working hours and the amount of (social) desynchronization induced by flexible work schedules can be used both for predicting the impairing effects of the specific work schedules on social well-being as well as for the design of socially acceptable flexible work hours.     

Genomic imprinting and kinship in the social Hymenoptera: what are the predictions?

The kinship theory of genomic imprinting predicts that conflicts of interest between parents can promote the evolution of opposed expression patterns of maternally and paternally derived alleles in the offspring. The social Hymenoptera (ants, some bees, and some wasps) are particularly suitable to test this theory, because a variety of social conflicts are predicted due to relatedness asymmetries between female and male nestmates that are a corollary of haplo-diploid sex determination. Here I argue that the kin-selection predictions for genomic imprinting in social Hymenoptera might in many cases be more complex than previously suggested, because the optimal strategy will have to take fitness effects in different castes and sexes into account.