Density dependence in Golden Eagle Aquila chrysaetos fecundity better explained by individual adjustment than territory heterogeneity

Density-dependence effects acting on fecundity can be explained by two competing hypotheses. The individual adjustment hypothesis (IAH) states that, as population density increases, interference among individuals negatively affects their breeding performance. The second hypothesis, the habitat heterogeneity hypothesis (HHH), proposes that, as more individuals occupy the space available, lower quality habitats are increasingly used, causing average population fecundity to decline. In territorial species, it is often predicted that interference mechanisms (IAH) should be of less importance than spatial heterogeneity (HHH). Here, we test this prediction in Golden Eagles, using 35 years of reproduction monitoring data from a population that has been recolonizing the grounds of a French National Park (Ecrins) in the Alps. During the study period, the Eagle population increased from c. 11 to 41 territorial pairs, providing a good opportunity to explicitly assess fecundity across a gradient of densities. Under the IAH, we expect the fecundity of all territories to diminish as density rises. Under strict HHH, older territories should maintain higher fecundity across time, and a positive relationship between fecundity and the seniority of a territory should be observed. A density-dependent pattern was clearly detected at the population level. At the territory level, the decrease of fecundity was strongly related to population size but not to territory seniority. Fecundity decreased similarly in all territories, suggesting that the IAH better explains the observed pattern. Two alternative mechanisms, related to the IAH, could be at play in this population: (1) negative interference by neighbours and non-territorial Eagles and (2) the contraction of individual territories over time. Our results provide new insights into density dependence in territorial raptors, suggesting that, in addition to habitat heterogeneity, interference mechanisms might actually also play an important role.     

Intracellular GSH levels rather than ROS levels are tightly related to AMA-induced HeLa cell death

Antimycin A (AMA) inhibits succinate oxidase and NADH oxidase, and also inhibits mitochondrial electron transport between cytochromes b and c. We investigated the involvement of ROS and GSH in AMA-induced HeLa cell death. AMA increased the intracellular H(2)O(2) and O(2)(*-) levels and reduced the intracellular GSH content. ROS scavengers (Tempol, Tiron, Trimetazidine and NAC) did not down-regulate the production of ROS and inhibit apoptosis in AMA-treated cells. Treatment with NAC and N-propylgallate showing the enhancement of GSH depletion in AMA-treated cells significantly intensified the levels of apoptosis. Calpain inhibitors I and II (calpain inhibitor III) and Ca(2+)-chelating agent (EGTA/AM) significantly reduced H(2)O(2) levels in AMA-treated HeLa cells. However, treatment with calpain inhibitor III intensified the levels of O(2)(*-) in AMA-treated cells. In addition, calpain inhibitor III strongly depleted GSH content with an enhancement of apoptosis in AMA-treated cells. Conclusively, the changes of ROS by AMA were not tightly correlated with apoptosis in HeLa cells. However, intracellular GSH levels are tightly related to AMA-induced cell death.     

Clinical symptoms in fibromyalgia are better associated to lipid peroxidation levels in blood mononuclear cells rather than in plasma

Background

We examined lipid peroxidation (LPO) in blood mononuclear cells (BMCs) and plasma, as a marker of oxidative damage, and its association to clinical symptoms in Fibromyalgia (FM) patients.

Methods

We conducted a case–control and correlational study comparing 65 patients and 45 healthy controls. Clinical parameters were evaluated using the Fibromyalgia Impact Questionnaire (FIQ), visual analogues scales (VAS), and the Beck Depression Inventory (BDI). Oxidative stress was determined by measuring LPO in BMCs and plasma.

Results

We found increased LPO levels in BMCs and plasma from FM patients as compared to normal control (P<0.001). A significant correlation between LPO in BMCs and clinical parameters was observed (r = 0.584, P<0.001 for VAS; r = 0.823, P<0.001 for FIQ total score; and r = 0.875, P<0.01 for depression in the BDI). We also found a positive correlation between LPO in plasma and clinical symptoms (r = 0.452, P<0.001 for VAS; r = 0.578, P<0.001 for FIQ total score; and r = 0.579, P<0.001 for depression in the BDI). Partial correlation analysis controlling for age and BMI, and sex, showed that both LPO in cells and plasma were independently associated to clinical symptoms. However, LPO in cells, but not LPO in plasma, was independently associated to clinical symptoms when controlling for depression (BDI scores).

Discussion

The results of this study suggest a role for oxidative stress in the pathophysiology of fibromyalgia and that LPO in BMCs rather than LPO in plasma is better associated to clinical symptoms in FM.     

Susceptibility to IDDM Is marked by MHC supratypes rather than individual alleles

107 patients with insulin-dependent diabetes mellitus (IDDM) were typed for HLA A, B, C, and DR antigens, and for complement C4A, C4B, and Bf alleles, and the results were compared with those of a combined reference group of 332 appropriately matched healthy subjects. Supratypes (allelic combinations) were identified from the phenotype of each group, and it was shown that the frequency of several supratypes is increased in patients with IDDM, in particular supratypes (A1 Cw7) B8 C4AQ0 C4B1 BfS DR3 (P = 0.0001), (A30 Cw-) B18 C4A3 C4BQ0 BfF1 DR3 (P = 0.0003), (A2 Cw3) B62 C4AR C4B2.9 BfS DR4 (P = 0.0002), and three other supratypes including DR4. It was also shown that increases in the frequency of individual alleles are secondary to increases in supratype frequency. Moreover, supratypes appeared to interact; the presence of two relevant supratypes being particularly important. The absolute risk of IDDM was approximately 0.5 in subjects who were homozygous for B18 C4A3 C4BQ0 BfF1 DR3. We concluded that genetic susceptibility is best recognized by MHC supratypes rather than isolated alleles, and that supratype combinations make the identification of even greater disease risk possible.     

Measuring individual inbreeding in the age of genomics: marker-based measures are better than pedigrees

Inbreeding (mating between relatives) can dramatically reduce the fitness of offspring by causing parts of the genome to be identical by descent. Thus, measuring individual inbreeding is crucial for ecology, evolution and conservation biology. We used computer simulations to test whether the realized proportion of the genome that is identical by descent (IBD_G) is predicted better by the pedigree inbreeding coefficient (F_P) or by genomic (marker-based) measures of inbreeding. Genomic estimators of IBD_G included the increase in individual homozygosity relative to mean Hardy–Weinberg expected homozygosity (F_H), and two measures (F_ROH and F_E) that use mapped genetic markers to estimate IBD_G. IBD_G was more strongly correlated with F_H, F_E and F_ROH than with F_P across a broad range of simulated scenarios when thousands of SNPs were used. For example, IBD_G was more strongly correlated with F_ROH, F_H and F_E (estimated with ⩾10 000 SNPs) than with F_P (estimated with 20 generations of complete pedigree) in populations with a recent reduction in the effective populations size (from N_e=500 to N_e=75). F_ROH, F_H and F_E generally explained >90% of the variance in IBD_G (among individuals) when 35 K or more SNPs were used. F_P explained <80% of the variation in IBD_G on average in all simulated scenarios, even when pedigrees included 20 generations. Our results demonstrate that IBD_G can be more precisely estimated with large numbers of genetic markers than with pedigrees. We encourage researchers to adopt genomic marker-based measures of IBD_G as thousands of loci can now be genotyped in any species.     

Replicating rather than nonreplicating adenovirus-human immunodeficiency virus recombinant vaccines are better at eliciting potent cellular immunity and priming high-titer antibodies

A major challenge in combating the human immunodeficiency virus (HIV) epidemic is the development of vaccines capable of inducing potent, persistent cellular immunity and broadly reactive neutralizing antibody responses to HIV type 1 (HIV-1). We report here the results of a preclinical trial using the chimpanzee model to investigate a combination vaccine strategy involving sequential priming immunizations with different serotypes of adenovirus (Ad)/HIV-1(MN)env/rev recombinants and boosting with an HIV envelope subunit protein, oligomeric HIV(SF162) gp140deltaV2. The immunogenicities of replicating and nonreplicating Ad/HIV-1(MN)env/rev recombinants were compared. Replicating Ad/HIV recombinants were better at eliciting HIV-specific cellular immune responses and better at priming humoral immunity against HIV than nonreplicating Ad-HIV recombinants carrying the same gene insert. Enhanced cellular immunity was manifested by a greater frequency of HIV envelope-specific gamma interferon-secreting peripheral blood lymphocytes and better priming of T-cell proliferative responses. Enhanced humoral immunity was seen in higher anti-envelope binding and neutralizing antibody titers and better induction of antibody-dependent cellular cytotoxicity. More animals primed with replicating Ad recombinants mounted neutralizing antibodies against heterologous R5 viruses after one or two booster immunizations with the mismatched oligomeric HIV-1(SF162) gp140deltaV2 protein. These results support continued development of the replicating Ad-HIV recombinant vaccine approach and suggest that the use of replicating vectors for other vaccines may prove fruitful.     

Longevity of orders is related to the longevity of their constituent genera rather than genus richness

Longevity of a taxonomic group is an important issue in understanding the dynamics of evolution. In this respect a key observation is that genera, families or orders can each be assigned a characteristic average lifetime (Van Valen in Evol Theory 1:1–30, 1973). Using the fossil marine animal genera database (Sepkoski in Bull Am Paleontol 363, pp 563, 2002) we here examine the relationship between longevity of a higher taxonomic group (orders) and the longevity of its lower taxonomic groups (genera). We find insignificant correlation between the size of an order and its longevity, whereas we observe large correlation between the lifetime of an order and the lifetime of its constituent genera. These observations suggest that longevity of taxonomic groups is heritable intrinsically or on the grounds of environmental preferences.     

TRFLP analysis reveals that fungi rather than bacteria are associated with premature yeast flocculation in brewing

Premature yeast flocculation (PYF) is a sporadic fermentation problem in the brewing industry that results in incomplete yeast utilization of fermentable sugars in wort. Culture-independent, PCR-based fingerprinting techniques were applied in this study to identify the associations between the occurrence of the PYF problem during brewery fermentation with barley malt-associated microbial communities (both bacteria and fungi). Striking differences in the microbial DNA fingerprint patterns for fungi between PYF positive (PYF +ve) and negative (PYF ?ve) barley malts were observed using the terminal restriction fragment length polymorphism (TRFLP) technique. The presence of terminal restriction fragments (TRFs) of 360–460 bp size range, for fungal HaeIII restriction enzyme-derived TRFLP profiles appeared to vary substantially between PYF +ve and PYF ?ve samples. The source of the barley malt did not influence the fungal taxa implicated in PYF. TRFLP analysis indicates bacterial taxa are unlikely to be important in causing PYF. Virtual digestion of fungal sequences tentatively linked HaeIII TRFs in the 360–460 bp size range to a diverse range of yeast/yeast-like species. Findings from this study suggest that direct monitoring of barley malt samples using molecular methods could potentially be an efficient and viable alternative for monitoring PYF during brewery fermentations.     

The stability of the ternary interferon-receptor complex rather than the affinity to the individual subunits dictates differential biological activities

Type I interferons (IFNs) signal for their diverse biological effects by binding a common receptor on target cells, composed of the two transmembrane IFNAR1 and IFNAR2 proteins. We have previously differentially enhanced the antiproliferative activity of IFN by increasing the weak binding affinity of IFN to IFNAR1. In this study, we further explored the affinity interdependencies between the two receptor subunits and the role of IFNAR1 in differential IFN activity. For this purpose, we generated a panel of mutations targeting the IFNAR2 binding site on the background of the IFNalpha2 YNS mutant, which increases the affinity to IFNAR1 by 60-fold, resulting in IFNAR2-to-IFNAR1 binding affinity ratios ranging from 1000:1 to 1:1000. Both the antiproliferative and antiviral potencies of the interferon mutants clearly correlated to the in situ binding IC(50) values, independently of the relative contributions of the individual receptors, thus relating to the integral lifetime of the complex. However, the antiproliferative potency correlated throughout the entire range of affinities, as well as with prolonged IFNAR1 receptor down-regulation, whereas the antiviral potency reached a maximum at binding affinities equivalent to that of wild-type IFNalpha2. Our data suggest that (i) the specific activity of interferon is related to the ternary complex binding affinity and not to affinity toward individual receptor components and (ii) although the antiviral pathway is strongly dependent on pSTAT1 activity, the cytostatic effect requires additional mechanisms that may involve IFNAR1 down-regulation. This differential interferon response is ultimately mediated through distinct gene expression profiling.     

Resource allocation in the submerged plant Vallisneria natans related to sediment type, rather than water-column nutrients

1. Phenotypic plasticity in resource allocation by Vallisneria natans was investigated in a greenhouse experiment, using three types of sediment [sandy loam, clay, and a 50 : 50 (by volume) mixture of the two sediments] and two levels of water‐column nutrient. The clay was collected from a highly eutrophic lake in Jiangsu Province, China, and the N and P concentrations applied in nutrient media were at the upper limits observed in most lakes of China. 2. Growth and biomass allocation were significantly affected by sediment type, rather than water‐column nutrients. Plant growth in clay and the mixture were similar, and 2.4–3.4 times higher than that in sandy loam. Compared with the plants grown in clay or the mixed sediments, the plants grown in sandy loam allocated relatively more biomass to root (11–17% versus 7–8% of total biomass), and relatively less to leaf (76–82% versus 86–87% of total biomass). Plastic variations in root area were induced by sediment type alone (P < 0.05), whereas the impacts of sediment type and water‐column nutrients on leaf area were insignificant (P > 0.05). 3. Plant N and P concentrations were significantly affected by both sediment type and water‐column nutrients. Increased nutrient availability in the water column enhanced plant N concentration by 3.5–20.2%, and plant P concentration by 19.1–25.8%. 4. Biomass accumulation and plant nutrient concentration in plants grown in different sediment types and water‐column nutrients indicate that sediment type had more significant impacts on growth and N and P concentrations of V. natans than did water‐column nutrients. Changes in phenotype are a functional response to nutrient availability in sediment, rather than to water‐column nutrients.     

Central rather than overall obesity is related to diabetes in the Chinese population: the InterASIA study

Objective: The objective was to compare central and overall obesity measurements for identifying diabetes mellitus (DM) and impaired fasting glucose (IFG) level in the Chinese population. Research Methods and Procedures: Data for 15,236 Chinese adults between the ages of 35 and 74 years, obtained by the InterASIA Study in 2000–2001, were used for the current analyses. We analyzed the areas under the receiver operating characteristic (ROC) curves (AUCs) for waist circumference (WC), waist‐to‐hip ratio (WHR), and BMI to determine the ability of these indices to identify DM and IFG in the study sample and bootstrapped samples. WC was used as a measure of central obesity and BMI as a measure of overall obesity. Results: The prevalence rates of central and overall obesity in the study population were 33.97% and 9.78%, respectively. The prevalence rates of IFG and DM were 7.34% and 5.51%, respectively. ROC analysis revealed significant differences between AUCs for WHR (0.666, 95% confidence interval, 0.647 to 0.685) and BMI (0.622, 95% confidence interval, 0.601 to 0.642) and for WC (0.661, 95% confidence interval, 0.643 to 0.682) and BMI for identifying DM (all p < 0.0001). The analysis also revealed significant differences between AUCs for WHR (0.638, 95% confidence interval, 0.619 to 0.655) and BMI (0.607, 95% confidence interval, 0.589 to 0.627) and for WC (0.637, 95% confidence interval, 0.615 to 0.654) and BMI for identifying IFG (all p < 0.001). Discussion: Central obesity is more related to DM and IFG than is overall obesity in the Chinese population, and both WC and WHR are equally able to identify DM.     

Re-citrate synthase from Clostridium kluyveri is phylogenetically related to homocitrate synthase and isopropylmalate synthase rather than to Si-citrate synthase

The synthesis of citrate from acetyl-coenzyme A and oxaloacetate is catalyzed in most organisms by a Si-citrate synthase, which is Si-face stereospecific with respect to C-2 of oxaloacetate. However, in Clostridium kluyveri and some other strictly anaerobic bacteria, the reaction is catalyzed by a Re-citrate synthase, whose primary structure has remained elusive. We report here that Re-citrate synthase from C. kluyveri is the product of a gene predicted to encode isopropylmalate synthase. C. kluyveri is also shown to contain a gene for Si-citrate synthase, which explains why cell extracts of the organism always exhibit some Si-citrate synthase activity.     

Ephelides are more related to pigmentary constitutional host factors than solar lentigines.

Ephelides and solar lentigines are benign pigmented spots, which are currently associated with an increased risk of skin cancer. These two pigmented spots are known to be discriminated by their clinical, histological, and electron microscopic characteristics, even though occasional misclassification can occur because of their similarity. It has also been questioned whether these spots are not one and the same. In this study, we have attempted to differentiate between these two pigmented spots with the use of a standardized protocol for clinical examinations on 272 healthy volunteers, paying particular consideration to their pigmentary and constitutional host factors. We found that solar lentigines 1) are more prevalent than ephelides, 2) increase in prevalence and number with higher age, and 3) are most prevalent on the trunk and occur more frequently in males than in females. A trend is also observed whereby ephelides 1) loose their prevalence with age, 2) become equally distributed on the face, arms, and trunk, and 3) occur more frequently in females. An intimate association of ephelides, but not solar lentigines, has been found with hair color and skin type. All of these findings are in agreement with most of those reported in the literature, supporting the view that ephelides and solar lentigines are different types of pigmented lesions.     

Abdominal microbial communities in ants depend on colony membership rather than caste and are linked to colony productivity

Gut bacteria aid their host in digestion and pathogen defense, and bacterial communities that differ in diversity or composition may vary in their ability to do so. Typically, the gut microbiomes of animals living in social groups converge as members share a nest environment and frequently interact. Social insect colonies, however, consist of individuals that differ in age, physiology, and behavior, traits that could affect gut communities or that expose the host to different bacteria, potentially leading to variation in the gut microbiome within colonies. Here we asked whether bacterial communities in the abdomen of Temnothorax nylanderi ants, composed largely of the gut microbiome, differ between different reproductive and behavioral castes. We compared microbiomes of queens, newly eclosed workers, brood carers, and foragers by high‐throughput 16S rRNA sequencing. Additionally, we sampled individuals from the same colonies twice, in the field and after 2 months of laboratory housing. To disentangle the effects of laboratory environment and season on microbial communities, additional colonies were collected at the same location after 2 months. There were no large differences between ant castes, although queens harbored more diverse microbial communities than workers. Instead, we found effects of colony, environment, and season on the abdominal microbiome. Interestingly, colonies with more diverse communities had produced more brood. Moreover, the queens' microbiome composition was linked to egg production. Although long‐term coevolution between social insects and gut bacteria has been repeatedly evidenced, our study is the first to find associations between abdominal microbiome characteristics and colony productivity in social insects.     

Fatty acid-induced defects in insulin signalling, in myotubes derived from children, are related to ceramide production from palmitate rather than the accumulation of intramyocellular lipid

The elevation of free fatty acids (FFAs), observed in childhood obesity results in intramyocellular lipid (IMCL) accumulation with consequent insulin resistance. Using in vitro differentiated myotubes from normal weight pre-pubertal children (n = 8), we examined the effects of saturated (palmitate) and unsaturated (oleate) FFAs on insulin-stimulated AKT phosphorylation (pAKT) and IMCL accumulation. Palmitate decreased pAKT (Mean [SEM] % change pAKT with palmitate 750 microM vs. control; pThr308 site -50.5% [28.7] and pSer473 site -38.7% [11.7]; P < 0.001) with no effect on IMCL formation. Equimolar bromopalmitate did not effect pAKT and blocking ceramide production abolished the palmitate-induced reduction in signalling, suggesting that ceramide synthesis is critical for palmitate's actions. Oleate did not effect pAKT (1,000 microM oleate; pSer473 site -3.4% [11.4]; P = NS) but increased IMCL accumulation (+32.3% [7.1%]; P < 0.001). Co-administration of oleate diminished the reduction in pAKT seen with palmitate (+36.4% [23.6] vs. -13.3% [13.6]; P = 0.28), with similar IMCL levels to oleate alone. Co-administration also caused a significant reduction in 14C-ceramide synthesis from 14C-palmitate (101.6 [21.6] vs. 371.5 [122.4] DPM/mg protein; P < 0.001). In summary, palmitate appears to cause insulin resistance in children's myotubes via its metabolism to ceramide, and this process appears unrelated to IMCL formation and is ameliorated by oleate.