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.     

Do women with acute myocardial infarction receive the same treatment as men?

OBJECTIVE--To determine whether women with acute myocardial infarction in the Nottingham health district receive the same therapeutic interventions as their male counterparts. DESIGN--Retrospective study. SETTING--University and City Hospitals, Nottingham. PATIENTS--All patients admitted with a suspected myocardial infarction during 1989 and 1990. MAIN OUTCOME MEASURES--Route and timing of admission to hospital, ward of admission, treatment, interventions in hospital, and mortality. RESULTS--Women with myocardial infarction took longer to arrive in hospital than men. They were less likely to be admitted to the coronary care unit and were therefore also less likely to receive thrombolytic treatment. They seemed to have more severe infarcts, with higher Killip classes, and had a slightly higher mortality during admission. They were less likely than men to receive secondary prophylaxis by being discharged taking beta blockers or aspirin. CONCLUSIONS--Survival chances both in hospital and after discharge in women with acute myocardial infarction are reduced because they do not have the same opportunity for therapeutic intervention as men.     

Do gymnosperm needles pull water through the xylem produced in the same year as the needle?

This research investigated the longevity of functional connections between leaf traces and stem xylem in 16 species of conifers to better understand the spatial use of sapwood for water transport. The first question was which ring(s) stained when a vacuum was applied to the distal end of the cut surface of a needle attached to a short stem segment. The vacuum was applied to either 1- or 2-yr-old foliage taken from 4-6-yr-old saplings. The 16 species were then categorized based on the growth ring that most consistently stained when the vacuum was applied to the 2-yr-old needles. There were three distinct stain patterns for the evergreen conifers and one pattern for the deciduous conifers. Three evergreen species could not be categorized. The second question used needle fall data to ask whether the leaf trace appeared to break because of age or stem diameter in 5-yr-old Pseudotsuga menziesii saplings. An apparent threshold stem diameter at which needles tended to be shed was more related to diameter than age. These xylem connection patterns could affect leaf cohort physiology and the spatial pattern of water flux in sapwood.     

Do ship strikes threaten the recovery of endangered eastern North Pacific blue whales?

Blue whales were targeted in the North Pacific from 1905–1971 and are listed as endangered by the IUCN. Despite decades without whaling, abundance estimates for eastern North Pacific (ENP) blue whales (Balaenoptera musculus) suggest little evidence for a recent increase. One possible reason is fatal strikes by large ships, which have affected populations of other cetaceans and resulted in mitigation. We used a population dynamics model to assess the trends and status of ENP blue whales, and the effects of ship strikes. We estimate the population likely never dropped below 460 individuals, and is at 97% of carrying capacity (95% interval 62%–99%). These results suggest density dependence, not ship strikes, is the key reason for the observed lack of increase. We also estimate future strikes will likely have a minimal impact; for example, an 11‐fold increase in vessels would lead to a 50% chance the long‐term population would be considered depleted. Although we estimate ship strike mitigation would have minimal impacts on population trends and status, current levels of ship strikes are likely above legal limits set by the U.S. The recovery of ENP blue whales from whaling demonstrates the ability of blue whale populations to rebuild under careful management.     

Lactic acid bacteria as probiotics for the nose?

Several studies have recently pointed towards an increased occurrence and prevalence of several taxa of the lactic acid bacteria (LAB) in the microbiota of the upper respiratory tract (URT) under healthy conditions versus disease. These include several species of the Lactobacillales such as Lacticaseibacillus casei, Lactococcus lactis and Dolosigranulum pigrum. In addition to physiological studies on their potential beneficial functions and their long history of safe use as probiotics in other human body sites, LAB are thus increasingly to be explored as alternative or complementary treatment for URT diseases. This review highlights the importance of lactic acid bacteria in the respiratory tract and their potential as topical probiotics for this body site. We focus on the potential probiotic properties and adaptation factors that are needed for a bacterial strain to optimally exert its beneficial activity in the respiratory tract. Furthermore, we discuss a range of in silico, in vitro and in vivo models needed to obtain better insights into the efficacy and adaptation factors specifically for URT probiotics. Such knowledge will facilitate optimal strain selection in order to conduct rigorous clinical studies with the most suitable probiotic strains. Despite convincing evidence from microbiome association and in vitro studies, the clinical evidence for oral or topical probiotics for common URT diseases such as chronic rhinosinusitis (CRS) needs further substantiation.     

Animal models of PD: pieces of the same puzzle?

Parkinson's disease (PD) is a common neurodegenerative disorder with no known cure. The etiology of PD is likely due, in part, to combinations of genetic susceptibilities and environmental factors. In rare familial cases, PD is due to genetic mutations. A number of new genetic and toxin models of PD and advances in older models are yielding important new information about the pathogenesis of PD. This has prompted us to critically review the current animal models for PD and discuss how these models may yield fresh insights into the pathogenesis of PD, as well as new therapeutic opportunities.     

Do oral bacteria alter the regenerative potential of stem cells? A?concise review

Mesenchymal stem cells (MSCs) are widely recognized as critical players in tissue regeneration. New insights into stem cell biology provide evidence that MSCs may also contribute to host defence and inflammation. In case of tissue injury or inflammatory diseases, e.g. periodontitis, stem cells are mobilized towards the site of damage, thus coming in close proximity to bacteria and bacterial components. Specifically, in the oral cavity, complex ecosystems of commensal bacteria live in a mutually beneficial state with the host. However, the formation of polymicrobial biofilm communities with pathogenic properties may trigger an inadequate host inflammatory‐immune response, leading to the disruption of tissue homoeostasis and development of disease. Because of their unique characteristics, MSCs are suggested as crucial regulators of tissue regeneration even under such harsh environmental conditions. The heterogeneous effects of bacteria on MSCs across studies imply the complexity underlying the interactions between stem cells and bacteria. Hence, a better understanding of stem cell behaviour at sites of inflammation appears to be a key strategy in developing new approaches for in situ tissue regeneration. Here, we review the literature on the effects of oral bacteria on cell proliferation, differentiation capacity and immunomodulation of dental‐derived MSCs.     

Do spatial effects appear at low dilution rate in chemostat?

The chemostat theory on two species competition has shown that the dilution rate where transition of dominance occurs – transition-dilution rate – is independent of limiting-nutrient concentration. However, we obtained the experimental data indicating that the transition-dilution rate changed with variations in limiting-ammonium concentrations, using the chemostat mixed-culture of the cyanobacterium Microcystis novacekii and the green alga Scenedesmus quadricauda. The transition-dilution rate was dependent on the concentration of limiting ammonium in the influx culture medium. We tried to simulate the experimental results. Though the dilution rate has been considered independent of nutrient concentration, we introduce the effective dilution rate that depends on nutrient concentration (ammonium concentration in this study). A hyperbolic Monod-type function is used to represent the effective dilution rate for each species. The maximum dilution rate of the function is set to be the mechanical dilution rate (nominal dilution rate) of the chemostat culture. The calculation shows that the nominal transition-dilution rate where transition of dominance occur decreases with increased concentration. This simulation is well consistent with our experimental data. These results may suggest that the species-specificity of limiting nutrients, here nitrogen. Or they may imply that the depreciation of nitrogen becomes critical when both dilution rate and concentration are very low, especially for the green algae. In the latter case, spatial effects are induced internally in the ecosystem.     

Energetics of gating at the apo–acetylcholine receptor transmitter binding site

Acetylcholine receptor channels switch between conformations that have a low versus high affinity for the transmitter and conductance for ions (R↔R*; gating). The forward isomerization, which begins at the transmitter binding sites and propagates ∼50 Å to the narrow region of the pore, occurs by approximately the same sequence of molecular events with or without agonists present at the binding sites. To pinpoint the forces that govern the R versus R* agonist affinity ratio, we measured single-channel activation parameters for apo-receptors having combinations of mutations of 10 transmitter binding site residues in the α (Y93, G147, W149, G153, Y190, C192, and Y198), ε (W55 and P121), or δ (W57) subunit. Gating energy changes were largest for the tryptophan residues. The αW149 energy changes were coupled with those of the other aromatic amino acids. Mutating the aromatic residues to Phe reduces the R/R* equilibrium dissociation constant ratio, with αY190 and αW149 being the most sensitive positions. Most of the mutations eliminated long-lived spontaneous openings. The results provide a foundation for understanding how ligands trigger protein conformational change.     

Is maximizing protection the same as minimizing loss? Efficiency and retention as alternative measures of the effectiveness of proposed reserves

We used two measures to compare the effectiveness of 52 conservation criteria in achieving conservation targets for forest types. The first measure was efficiency. Although widely used, efficiency assumes no loss or reduction of biodiversity features before conservation is implemented. This is invalid in many situations. Often, it is more realistic to assume gradual implementation accompanied by incremental, predictable reduction and loss of biodiversity features. We simulated future landscapes resulting from the annual interplay of loss and conservation of forest types. We then based our second measure, retention, on how well criteria scheduled conservation action to prevent targets being compromised. The simulations partly support predictions about the best criteria for scheduling implementation with continuing biodiversity loss. Retention was weakly related or unrelated to efficiency across 52 criteria. Although retention values were sensitive to changes in targets and rates of conservation and forest loss, one criterion consistently produced highest retention values.     

Do bacteria differentiate between degrees of nanoscale surface roughness?

Whereas the employment of nanotechnology in electronics and optics engineering is relatively well established, the use of nanostructured materials in medicine and biology is undoubtedly novel. Certain nanoscale surface phenomena are being exploited to promote or prevent the attachment of living cells. However, as yet, it has not been possible to develop methods that completely prevent cells from attaching to solid surfaces, since the mechanisms by which living cells interact with the nanoscale surface characteristics of these substrates are still poorly understood. Recently, novel and advanced surface characterisation techniques have been developed that allow the precise molecular and atomic scale characterisation of both living cells and the solid surfaces to which they attach. Given this additional capability, it may now be possible to define boundaries, or minimum dimensions, at which a surface feature can exert influence over an attaching living organism.This review explores the current research on the interaction of living cells with both native and nanostructured surfaces, and the role that these surface properties play in the different stages of cell attachment.     

Do stress-whitening and optical clearing of collagenous tissue occur by the same mechanism?

Bone is biphasic with an organic matrix and an inorganic mineral component. As we age bone's susceptibility to fracture increases. It has been shown that there is no change in mean mineralization with aging, but bone nevertheless becomes less tough. This aging effect is therefore likely related to the organic phase.     

Evolution: What determines the rate of sequence evolution?

High rates of amino-acid sequence evolution have sometimes been considered to be diagnostic for genes undergoing adaptive change. However, two recent studies have shown that rapid evolution of amino-acid sequence can also be congruent with neutrality.     

Biogeography at the limits of life: Do extremophilic microbial communities show biogeographical regionalization?

Aim

Biogeographical regions are the fundamental geographical units for grouping Earth's biodiversity. Biogeographical regionalization has been demonstrated for many higher taxa, such as terrestrial plants and vertebrates, but not in microbial communities. Therefore, we sought to test empirically whether microbial communities, or taxa, show patterns consistent with biogeographical regionalization.

Location

Within halite (NaCl) crystals from coastal solar salterns of western Europe, the Mediterranean and east Africa.

Time period

Modern (2006–2013).

Major taxa studied

Archaea.

Methods

Using high‐throughput Illumina amplicon sequencing, we generated the most high‐resolution characterization of halite‐associated archaeal communities to date, using samples from 17 locations. We grouped communities into biogeographical clusters based on community turnover to test whether these communities show biogeographical regionalization. To examine whether individual taxa, rather than communities, show biogeographical patterns, we also tested whether the relative abundance of individual genera may be indicative of a community's biogeographical origins using machine learning methods, specifically random forest classification.

Results

We found that the rate of community turnover was greatest over subregional spatial scales (< 500 km), whereas at regional spatial scales the turnover was independent of geographical distance. Biogeographical clusters of communities were either not statistically robust or lacked spatial coherence, inconsistent with biogeographical regionalization. However, we identified several archaeal genera that were good indicators of biogeographical origin, providing classification error rates of < 10%.

Main conclusions

Overall, our results provide little support for the concept of biogeographical regions in these extremophilic microbial communities, despite the fact that some taxa do show biogeographical patterns. We suggest that variable dispersal ability among the halite‐associated Archaea may disrupt biogeographical patterns at the community level, preventing the formation of biogeographical regions. This means that the processes that lead to the formation of biogeographical regions operate differentially on individual microbial taxa rather than on entire communities.     

Native and alien invasive plants: more of the same?

We compare the ecological and habitat characteristics of alien and native vascular plants which have recently expanded in range m England, Scotland, the Republic of Ireland and the Netherlands In the great majority of respects, expanding aliens and natives are functionally indistinguishable However, there are a few consistent differences aliens are more likely than natives to be clonal, polycarpic perennials with erect, leafy stems, and to have transient seed banks We discuss these trends m the context of the difficulties faced by aliens in invading mostly closed plant communities in relatively cool, damp climates Our results are consistent with some predictions of the attributes of'ideal'invaders, but contradict others We argue that the ecological attributes of successful alien invaders are strongly habitat-dependent     

Tumorigenesis and neurodegeneration: two sides of the same coin?

Dysregulation of genes that control cell-cycle progression and DNA repair is a hallmark of tumorigenesis. It is becoming increasingly apparent, however, that these defects also contribute to degeneration of post-mitotic neurons under certain conditions. The gene for ataxia-telangiectasia mutated (ATM) is a prototype for this dual mechanism of action, with loss-of-function mutations causing not only selective degeneration of cerebellar neurons but also increased susceptibility to breast cancer and hematologic malignancy. Increased dosage of amyloid precursor protein in Down syndrome (trisomy 21) predisposes to dementia of Alzheimer type and may also contribute to acute leukemia and transient myeloproliferative disorder. The gene parkin, loss-of-function mutations in which account for about half of cases of early-onset Parkinson disease, has been identified as a candidate tumor suppressor gene by several groups. Parkin is deleted or downregulated in several tumor types, and its re-expression sensitizes derivative cell lines to inhibitors of cell-cycle progression. The overlap of molecular pathways implicated in cancer and neurodegeneration challenges long-held notions about differentiated cellular states and may open the door to novel therapeutic approaches to both groups of disorders.