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1.
The role of the mitochondria in disease, general health and aging has drawn much attention over the years. Several attempts have been made to describe how the numbers of mitochondria correlate with age, although with inconclusive results. In this study, the relative quantity of mitochondrial DNA compared to nuclear DNA, i.e. the mitochondrial DNA copy number, was measured by PCR technology and used as a proxy for the content of mitochondria copies. In 1,067 Danish twins and singletons (18–93 years of age), with the majority being elderly individuals, the estimated mean mitochondrial DNA copy number in peripheral blood cells was similar for those 18–48 years of age [mean relative mtDNA content: 61.0; 95 % CI (52.1; 69.9)], but declined by ?0.54 mtDNA 95 % CI (?0.63; ?0.45) every year for those older than approximately 50 years of age. However, the longitudinal, yearly decline within an individual was more than twice as steep as observed in the cross-sectional analysis [decline of mtDNA content: ?1.27; 95 % CI (?1.71; ?0.82)]. Subjects with low mitochondrial DNA copy number had poorer outcomes in terms of cognitive performance, physical strength, self-rated health, and higher all-cause mortality than subjects with high mitochondrial DNA copy number, also when age was controlled for. The copy number mortality association can contribute to the smaller decline in a cross-sectional sample of the population compared to the individual, longitudinal decline. This study suggests that high mitochondrial DNA copy number in blood is associated with better health and survival among elderly.  相似文献   

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Although many species of marine mega-vertebrates are threatened as a result of human activity, some populations are showing promising signs of recovery following decades of protection. In this study, we report on the status of the South Atlantic’s largest green turtle (Chelonia mydas) nesting aggregation at Ascension Island, 70 years after legal protection and the cessation of commercial turtle harvesting that decimated the population. Using a monitoring dataset spanning 36 years, we modelled long-term trends in nesting activity at both a rookery level and across individual nesting beaches and beach clusters. Since monitoring began in 1977, the average number of green turtle clutches deposited annually at Ascension Island has increased sixfold, from approximately 3,700 to 23,700; a trend that has been accompanied by a significant decrease in the average size of nesting females. Interestingly, however, rates of increase in nesting activity have varied dramatically among nesting beaches, ranging from 0.4 to 6 % growth per annum. More than 97 % of this variation could be explained by distance from the main human settlement of Georgetown—the historic centre of turtle harvesting—with beaches closer to Georgetown experiencing the most rapid growth. More rapid population growth close to human centres seems counterintuitive, but may reflect the more intensive depletion of these accessible, local stocks during the harvesting era. Overall, the Ascension Island green turtle population appears to be recovering strongly, mirroring positive trends for this species across many parts of its geographic range. While not a cause for complacency, these trends are encouraging and demonstrate the capacity of marine megafauna to rebound when anthropogenic pressures are alleviated through conservation action.  相似文献   

4.
Grasslands provide many ecosystem services including carbon storage, biodiversity preservation and livestock forage production. These ecosystem services will change in the future in response to multiple global environmental changes, including climate change and increased nitrogen inputs. We conducted an experimental study over 3 years in a mesotrophic grassland ecosystem in southern England. We aimed to expose plots to rainfall manipulation that simulated IPCC 4th Assessment projections for 2100 (+15 % winter rainfall and ?30 % summer rainfall) or ambient climate, achieving +15 % winter rainfall and ?39 % summer rainfall in rainfall-manipulated plots. Nitrogen (40 kg ha?1 year?1) was also added to half of the experimental plots in factorial combination. Plant species composition and above ground biomass were not affected by rainfall in the first 2 years and the plant community did not respond to nitrogen enrichment throughout the experiment. In the third year, above-ground plant biomass declined in rainfall-manipulated plots, driven by a decline in the abundances of grass species characteristic of moist soils. Declining plant biomass was also associated with changes to arthropod communities, with lower abundances of plant-feeding Auchenorrhyncha and carnivorous Araneae indicating multi-trophic responses to rainfall manipulation. Plant and arthropod community composition and plant biomass responses to rainfall manipulation were not modified by nitrogen enrichment, which was not expected, but may have resulted from prior nitrogen saturation and/or phosphorus limitation. Overall, our study demonstrates that climate change may in future influence plant productivity and induce multi-trophic responses in grasslands.  相似文献   

5.
Management of harvested wildlife populations aims to protect species from overexploitation and ultimately extinction, by regulating exploitation towards achievable sustainable levels. However, assessments of impact and sustainability of implemented management actions on a population level are scarce. This study assesses effects of changes in hunting season length imposed on the Baltic-Wadden Sea Common Eider Somateria mollissima population, including differential restriction on hunting of the sexes. The potential impact of these changes on the population was assessed by simple demographic matrix projections. Since the early 1990s, this population has declined at ca. 6.3 % per annum, and the male/female ratio among shot birds has fallen from 3:2 to about 3:1. Concerns in Denmark regarding the conservation status and sustainability of contemporary levels of exploitation resulted in shortening the open season by 44 and 46 days for females and 13 and 15 days for males from the hunting seasons 2004/2005 and 2011/2012 onwards, respectively. These reduced the kill of adult females by 82 %, adult males by 31 %, juvenile females by 58 % and juvenile males by 55 %. The observed reduction in the kill of adult females following both changes in 2004/2005 and 2011/2012 matched the expected changes based on the seasonal distribution of sexes in the bag prior to the change. Post 2004/2005 hunters killed more adult males, but shot markedly fewer juvenile birds than expected. Demographic modelling of the female population showed that the effects of the reduced hunting would correspond to an increase in the annual population growth rate from the previous ?6.3 to ?3.6 % (post 2004) and ?1.6 % (post 2011). The model also predicted that a full ban on hunting female eiders (adults and juveniles) would lead to a positive population growth rate of 0.7 %. Taking into account the conservative model estimates and natural variations in annual breeding success, the implemented changes in sex-specific regulation of hunting may potentially be an effective management tool to halt the decline of the Baltic-Wadden Sea eider population, potentially rendering such levels of hunting sustainable under prevailing conditions.  相似文献   

6.
Susceptibility of human metabolic phenotypes to dietary modulation   总被引:1,自引:0,他引:1  
Dietary composition has been shown to influence metabolism and to impact on the prevalence and risk for certain diseases, but hitherto, there have been no systematic studies on the effects of dietary modulation of human metabolic phenotype (metabotype). Here, we have applied 1H NMR spectroscopy in combination with multivariate statistical analysis to characterize the effects of three diets: "vegetarian", "low meat", and "high meat" on the metabotype signature of human participants. Twelve healthy male participants (age range of 25-74 years) consumed each of these diets, in a randomized order, for continuous 15-day-periods with an intervening washout period between each diet of 7 days duration. Each participant provided three consecutive 24-hour urine collections on days 13, 14, and 15 of each dietary period, and 1H NMR spectra were acquired on all samples. Pattern recognition analysis allowed differentiation of the characteristic metabolic signatures of the diets with creatine, carnitine, acetylcarnitine, and trimethylamine-N-oxide (TMAO) being elevated in the high-meat consumption period. Application of orthogonal projection to latent structure discriminant analysis (O-PLS-DA) allowed the low-meat diet and vegetarian diet signatures to be characterized, and p-hydroxyphenylacetate (a microbial mammalian cometabolite) was higher in the vegetarian than meat diet samples, signaling an alteration of the bacterial composition or metabolism in response to diet. This work shows the potential for the routine use of metabonomics in nutritional and epidemiological studies, in characterizing and predicting the metabolic effects and the influence of diet on human metabotypes.  相似文献   

7.
The aims of this study were to evaluate the effects of the addition of metabolic precursors and polydimethylsiloxane (PDMS) as an oxygen carrier to cultures of Bacillus subtilis BL53 during the production of γ-PGA. Kinetics analyses of cultivations of different media showed that B. subtilis BL53 is an exogenous glutamic acid-dependent strain. When the metabolic pathway precursors of γ-PGA synthesis, l-glutamine and a-ketoglutaric acid, were added to the culture medium, production of the biopolymer was increased by 20 % considering the medium without these precursors. The addition of 10 % of the oxygen carrier PDMS to cultures caused a two-fold increase in the volumetric oxygen mass transfer coefficient (kLa), improving γ-PGA production and productivity. Finally, bioreactor cultures of B. subtilis BL53 adopting the combination of optimized medium E, added of glutamine, α-ketoglutaric acid, and PDMS, showed a productivity of 1 g L?1 h?1 of g-PGA after only 24 h of cultivation. Results of this study suggest that the use of metabolic pathway precursors glutamine and a-ketolgutaric acid, combined with the addition of PDMS as an oxygen carrier in bioreactors, can improve γ-PGA production and productivity by Bacillus strains .  相似文献   

8.
Population genetic analysis in the important endangered medicinal and aromatic plant species, Valeriana jatamansi, provided, first time, insights into the identification of novel sources of genetic variation as an aid for improvement and domestication, and for optimizing conservation strategies. The 75 genotypes of V. jatamansi were collected from 36 locations across northeast to northwest Indian Himalayas of ~1,000 km, harbouring variable climatic and ecological conditions and rugged rocky terrain. The known protocols for DNA extraction failed to yield quality DNA in good quantity. A new protocol was standardized for this purpose. All the three (RAPD, ISSR, AFLP) DNA markers were successful in detecting polymorphism in V. jatamansi genotypes, and the ISSR marker, vis-à-vis RAPD and AFLP markers, generated the highest level of polymorphism. The RAPD, ISSR and AFLP fingerprints with 23 and 15 primers and 8 primer combinations, respectively, revealed 85.8, 89.0 and 67.7 % polymorphism among 141, 91 and 37 genetic loci amplified from the 75 genotypes, respectively. The AMOVA analysis of AFLP (55.0, 8.3, 36.7 %), RAPD (57.4, 11.9, 30.6 %) and ISSR (76.0, 4.8, 19.1 %) data indicated that more variation existed in differences in genotypes within populations than between populations within a region and between regions, respectively. The present comprehensive input will assist in effective management and (or) devising conservation strategies of this important medicinal plant species. This study reports the start of a molecular biology programme targeting nuclear genome of V. jatamansi, the genetics of which is very little known.  相似文献   

9.
Reefs of Andaman and Nicobar Islands harbour 418 species of scleractinian corals spread over an area of 2,000 km2. In April to May, 2010, due to the delayed onset of the southwest monsoon the sea surface temperature of the coastal and oceanic region increased to 31.7 °C in respect to the earlier record of maximum 29.0 °C during the said period. This resulted in mass bleaching of hermatypic corals during May, 2010. Rapid under water surveys have been conducted in reefs of Andaman and Nicobar Islands to assess the health of corals between May 2010 and August 2011. It is estimated that 76.62 ± (SD) 10.83 % of coral species are bleached up to a water depth of 10–15 m. Species from the genus Acropora appeared more susceptible to bleaching than those belong to the genus Porites. During the month of June 2010 the sea surface temperature was reduced to 29 °C perhaps due to the rainfall which stimulated rebuilding of zooxanthellae population in bleached corals. Recovery of 85.54 ± (SD) 6.33 % of bleached corals was seen during the study period of 11 months after the bleaching event. Porites spp. showed a high recovery rate, while Acropora spp. had the highest mortality rate. Coral mortality can have profound ecological and socio-economical implications and highlights the need for sustained monitoring for coral reef conservation in India. Hence, steps must be taken to improve management tools to protect these resources of global significance.  相似文献   

10.
Studies using animal models have demonstrated that ingestion of bovine lactoferrin (bLF) inhibits carcinogenesis in the colon and other organs of experimental animals. As a result of these studies, a blinded, randomized, controlled clinical trial was conducted in the National Cancer Center Hospital, Tokyo, Japan to determine whether ingestion of bLF had an effect on the growth of colorectal polyps in humans. Patients with colorectal polyps ≤5 mm diameter and likely to be adenomas ingested 0, 1.5, or 3.0 g bLF daily for 1 year. Ingestion of 3.0 g bLF suppressed the growth of colorectal polyps and increased the level of serum human lactoferrin in trial participants 63 years old or younger. The purpose of the present study was to investigate correlations between immune parameters and changes in polyp size. Trial participants with regressing polyps had increased NK cell activity, increased serum hLF levels (indicating increased neutrophil activity), and increased numbers of CD4+ cells in the polyps. These findings are consistent with a correlation between higher immune activity and suppression of colorectal polyps. In addition, participants with regressing polyps had lower numbers of PMNs and increased numbers of S100A8+ cells in the polyps, consistent with a correlation between lower inflammatory potential in the colon and suppression of colorectal polyps. Trial participants ingesting bLF had increased serum hLF levels, a possible increase in systemic NK cell activity, and increased numbers of CD4+ and CD161+ cells in the polyps. Taken together, our findings suggest that bLF suppressed colorectal polyps by enhancing immune responsiveness.  相似文献   

11.
Kawasaki disease is a pediatric systemic vasculitis of unknown etiology, for which a genetic influence is suspected. But whether single nucleotide polymorphism (SNP) of caspase-3 rs72689236 is associated with Kawasaki disease is controversial. The aim of our study is to assess the association between the SNP of caspase-3 and risk for Kawasaki disease. We searched PubMed, MEDLINE, EMBASE, Springer, Elsevier Science Direct, Cochrane Library Google scholar, CNKI (China National Knowledge Infrastructure, in Chinese) and Wanfang database (in Chinese) to identify studies investigating the association between rs72689236 polymorphism and Kawasaki disease occurrence. There were five eligible studies, which included 4,241 (case group 1,560; control group 2,681) participants in this meta-analysis. Pooled odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were calculated in a fixed-effects model (the Mantel–Haenszel method) or a random-effects model (the DerSimonian and Laird method) when appropriate. Significant associations were found under the overall ORs for A-allele comparison (A vs. G, pooled OR 1.33, 95 % CI 1.21–1.46), AA versus GG comparison (pooled OR 1.64, 95 % CI 1.35–2.00), GA versus GG comparison (pooled OR 1.42, 95 % CI 1.24–1.63), recessive model (AA vs. GG + GA, pooled OR 1.37, 95 % CI 1.15–1.64) and dominant model (AA + GA vs. GG, pooled OR 1.47, 95 % CI 1.29–1.67). This meta-analysis suggested that SNP rs72689236 of caspase-3 might be associated with susceptibility of Kawasaki disease and the allele A might increase the risk of Kawasaki disease in Asian samples such as Japanese and Chinese. In addition, individual studies with large sample size are needed to further evaluate the associations in various ethnic populations.  相似文献   

12.
Elkhorn coral, Acropora palmata, relies heavily on clonal propagation and often displays low genotypic (clonal) diversity. Populations in the Florida Keys experienced rapid declines in tissue cover between 2004 and 2006, largely due to hurricanes and disease, but remained stable from 2006 to 2010. All elkhorn colonies in 150 m2 permanent study plots were genotyped in 2006 (n = 15 plots) and 2010 (n = 24 plots), and plots sampled in both years were examined for changes in allelic and genotypic diversity during this period of stable ecological abundance. Overall, genetic diversity of Florida plots was low and declined further over the 4-yr period; seven of the 36 original genets and two of 67 alleles (among five microsatellite loci) were lost completely from the sampled population, and an additional 15 alleles were lost from individual reefs. In 2010, Florida plots (~19 colonies) contained an average of 2.2 ± 1.38 (mean ± SD) genets with a significant negative correlation between colony abundance and genotypic diversity. When scaled to total tissue abundance, genotypic diversity is even lower, with 43 % of genets below the size of sexual maturity. We examined the hypothesized positive relationship of local genotypic diversity with ecological performance measures. In Florida plots (n = 15), genotypic diversity was not significantly correlated with tissue loss associated with chronic predation, nor with acute disease and storm-fragmentation events, though this relationship may be obscured by the low range of observed diversity and potential confounding with abundance. When more diverse plots in Curaçao (n = 9) were examined, genotypic diversity was not significantly correlated with resistance during an acute storm disturbance or rate of recovery following disturbance. Cryptic loss of genetic diversity occurred in the apparently stable Florida population and confirms that stable or even increasing abundance does not necessarily indicate genetic stability.  相似文献   

13.
Mosquito coils are insecticides commonly used for protection against mosquitoes due to their toxic effects on mosquito populations. These effects on mosquitoes could induce the expression of metabolic enzymes in exposed populations as a counteractive measure. Cytochrome P450 family 4 (CYP4) are metabolic enzymes associated with a wide range of biological activities including insecticide resistance. In this study, the efficacies of three commercial mosquito coils with different pyrethroid active ingredients were assessed and their potential to induce the expression of CYP4 genes in Aedes albopictus analyzed by real-time quantitative PCR. Coils containing 0.3 % d-allethrin and 0.005 % metofluthrin exacted profound toxic effects on Ae. albopictus, inducing high mortalities (≥90 %) compared to the 0.2 % d-allethrin reference coil. CYP4H42 and CYP4H43 expressions were significantly higher in 0.3 % d-allethrin treated mosquitoes compared to the other treated populations. Short-term (KT50) exposure to mosquito coils induced significantly higher expression of both genes in 0.005 % metofluthrin exposed mosquitoes. These results suggest the evaluated products provided better protection than the reference coil; however, they also induced the expression of metabolic genes which could impact negatively on personal protection against mosquito.  相似文献   

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MapReduce is an effective tool for processing large amounts of data in parallel using a cluster of processors or computers. One common data processing task is the join operation, which combines two or more datasets based on values common to each. In this paper, we present a network aware multi-way join for MapReduce (SmartJoin) that improves performance and considers network traffic when redistributing workload amongst reducers. SmartJoin achieves this by dynamically redistributing tuples directly between reducers with an intelligent network aware algorithm. We show that our presented technique has significant potential to minimize the time required to join multiple datasets. In our evaluation, we show that SmartJoin has up to 39 % improvement compared to the non-redistribution method, a 26.8 % improvement over random redistribution and 27.6 % improvement over worst join redistribution.  相似文献   

17.

Background

Candida species represent the fourth leading cause of nosocomial bloodstream infections (BSI) worldwide. However, candidaemia rates and species involved vary geographically.

Objectives

To evaluate the epidemiological pattern, risk factors for mortality and antifungal therapy of Candida BSI over a 5-year period (2008–2012) in a university hospital in northern Italy together with a review of the recent literature concerning candidaemia.

Methods

A retrospective cohort study cross-linked with microbiology database was performed.

Results

A total of 89 Candida BSI were identified in 42 males (47 %) and 47 females (52.8 %). The median age was 69 years (interquartile range 55–78) with 61.8 % of patients being older than 65 years. Considering all hospitalized patients, the overall incidence rate of candidaemia increased significantly from 2008 to 2012 (from 0.4 to 1.68 episodes per 10,000 patient/days) (p = 0.0001) with a mean linear increase in 5 new cases per year. Candida albicans was the predominant species isolated (64 %) followed by C. glabrata (19.1 %). The latter species was observed with significantly higher frequency in Internal Medicine and Intensive Care Units (ICU). In-hospital crude mortality was 41.6 %.

Conclusions

Candidaemia is an increasing BSI in our university hospital, in accordance with that observed in northern Italy, and it is still associated with high in-hospital crude mortality.  相似文献   

18.
Findings from research in animal models and humans have shown a clear role for the neuropeptide oxytocin (OT) on complex social behaviors. This is also true in the context of autism spectrum disorder (ASD). Previous studies on peripheral OT concentrations in children and young adults have reported conflicting results with the initial studies presenting mainly decreased OT plasma levels in ASD compared to healthy controls. Our study therefore aimed to further investigate changes in peripheral OT concentrations as a potential surrogate for the effects observed in the central nervous system (CNS) in ASD. OT plasma concentrations were assessed in 19 male children and adolescents with ASD, all with an IQ > 70 (age 10.7 ± 3.8 years), 17 healthy male children (age 13.6 ± 2.1 years) and 19 young male patients with attention deficit hyperactivity disorder (ADHD) as a clinical control group (age 10.4 ± 1.9 years) using a validated radioimmunoassay. Analysis of covariance revealed significant group differences in OT plasma concentrations (F(2, 48) = 9.574, p < 0.001, η 2 = 0.285; plasma concentrations ASD 19.61 ± 7.12 pg/ml, ADHD 8.05 ± 5.49 pg/ml, healthy controls 14.43 ± 9.64 pg/ml). Post hoc analyses showed significantly higher concentrations in children with ASD compared to ADHD (p < 0.001). After Bonferroni correction, there was no significant difference in ASD in comparison with healthy controls (p = 0.132). A significant strong correlation between plasma OT and autistic symptomatology, assessed by the Autism Diagnostic Observation Schedule, was observed in the ASD group (p = 0.013, r = 0.603). Patients with ADHD differed from healthy control children by significantly decreased OT concentrations (p = 0.014). No significant influences of the covariates age, IQ, medication and comorbidity could be seen. Our preliminary results point to a correlation of OT plasma concentrations with autistic symptom load in children with ASD and a modulation of the OT system also in the etiologically and phenotypically overlapping disorder ADHD. Further studies in humans and animal models are warranted to clarify the complex association of the OT system with social impairments as well as stress-related and depressive behavior and whether peripheral findings reflect primary changes of OT synthesis and/or release in relevant areas of the CNS.  相似文献   

19.

Background

Although symptomatic patients with severe aortic stenosis have a high disease burden and guidelines recommend aortic valve replacement, many are treated conservatively. This study describes to what extent quality of life is changed by aortic valve replacement relative to conservative treatment.

Methods

This observational study followed 132 symptomatic patients with severe aortic stenosis who were subjected to an SF-36v2TM Health Survey.

Results

At baseline 84 patients were treated conservatively, 48 were referred for aortic valve replacement. In the conservatively treated group 15 patients died during a mean follow-up of 18 months (Kaplan-Meier survival was 85 % and 72 % at one and 2 years respectively) and 22 patients crossed over to the surgical group. Of the resulting 70 patients in the surgical group 3 patients died during a mean follow-up of 11 months (survival 95 % at 1 year). Physical functioning, vitality and general health improved significantly 1 year after aortic valve replacement. In conservatively treated patients physical quality of life deteriorated over time while general health, vitality and social functioning showed a declining trend. Mental health remained stable in both groups.

Conclusions

Aortic valve replacement improves physical quality of life, general health and vitality in patients with symptomatic severe aortic stenosis. Besides having a low life expectancy, conservatively treated patients experience deterioration of physical quality of life. Health surveys such as the SF-36v2TM can be valuable tools in monitoring the burden of disease for an individual patient and offer additional help in treatment decisions.  相似文献   

20.
Glycine max is one of the major sources of phytochemicals, in particular of isoflavones, a class of phytoestrogens with ascertained beneficial effects on human health. In the present study, in vitro callus production from soybean hypocotyl seedling explants and cell suspensions were optimized. Time-courses having 20, 40 and 60 g/L of initial cell inoculum were performed to determine the concentration most suitable for isoflavone production. The amount of total polyphenols and total flavonoids as well as the antioxidant capacity of both cell and culture media fractions were measured by means of spectrophotometric methods. The levels of aglycone and glycosylated isoflavones (didzein, genistein, glycitein, didzin, genistin, glycitin), as well as of ferulic acid, vanillic acid and vanillin, were determined by HPLC–DAD. On average, 93.5 % of the total (cells plus media) isoflavones in soybean cell suspensions were detected as aglycones. Concentrated cell cultures as well as industrial soybean seed extracts were enzymatically hydrolyzed to release the aglycones and their metabolic profiles were analysed by HPLC–DAD. In contrast to cell suspensions, in undigested seed extract the aglycon form represented only 16.8 % of the total isoflavones amount. After enzymatic treatment, the antioxidant capacity increased by 30 and 33 %, respectively, in concentrated cell and seed extracts, demonstrating the presence of a larger amount of bioactive metabolites after digestion. At the present extraction conditions, soybean concentrated cell suspensions yielded 5.8-fold more total isoflavones (mostly in the free form) than seed extracts, leading to hypothesise their possible use as ingredients for cosmetic and nutraceutical applications.  相似文献   

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