Localization of ORC1 during the cell cycle in human leukemia cells

The interaction of the origin recognition complex (ORC) with replication origins is a critical parameter in eukaryotic replication initiation. In mammals the ORC remains bound except during mitosis, thus the localization of ORC complexes allows localization of origins. A monoclonal antibody that recognizes human ORC1 was used to localize ORC complexes in populations of human MOLT-4 cells separated by cell cycle position using centrifugal elutriation. ORC1 staining in cells in early G1 is diffuse and primarily peripheral. As the cells traverse G1, ORC1 accumulates and becomes more localized towards the center of the nucleus, however around the G1/S boundary the staining pattern changes and ORC1 appears peripheral. By mid to late S phase ORC1 immunofluorescence is again concentrated at the nuclear center. During anaphase, ORC1 staining is localized mainly in the pericentriolar regions. These findings suggest that concerted movements of origin DNA sequences in addition to the previously documented assembly and disassembly of protein complexes are an important aspect of replication initiation loci in eukaryotes.     

Geographic variation in cardiovascular inflammation among healthy women in the Women's Health Study

Background

Geographic variation in traditional cardiovascular disease (CVD) risk factors has been observed among women in the US. It is not known whether state-level variation in cardiovascular inflammation exists or could be explained by traditional clinical risk factors and behavioral lifestyle factors.

Methods and Results

We used multilevel linear regression to estimate state-level variation in inflammatory biomarker patterns adjusted for clinical and lifestyle characteristics among 26,029 women free of CVD. Participants derived from the Women''s Health Study, a national cohort of healthy middle-aged and older women. Inflammatory biomarker patterns (plasma levels of high-sensitivity C-reactive protein (hsCRP), soluble intercellular adhesion molecule-1 (sICAM-1), and fibrinogen) were compared to state-level patterns of traditional CVD risk factors and global risk scores. We found that all three inflammatory biomarkers exhibited significant state-level variation including hsCRP (lowest vs. highest state median 1.3 mg/L vs. 2.7 mg/L, unadjusted random effect estimate 1^st to 99^th percentile range for log hsCRP 0.52, p<.001), sICAM-1 (325 ng/ml vs. 366ng/ml, unadjusted random effect estimate 1^st to 99^th percentile range 0.44, p<.001), and fibrinogen (322 mg/dL vs. 367 mg/dL, unadjusted random effect estimate 1^st to 99^th percentile range 0.41, p = .001). Neither demographic, clinical or lifestyle characteristics explained away state-level effects in biomarker patterns. Southern and Appalachian states (Arkansas, West Virginia) had the highest inflammatory biomarker values. Regional geographic patterns of traditional CVD risk factors and risk scores did not completely overlap with biomarkers of inflammation.

Conclusions

There is state-level geographic variation in inflammatory biomarkers among otherwise healthy women that cannot be completely attributed to traditional clinical risk factors or lifestyle characteristics. Future research should aim to identify additional factors that may explain geographic variation in biomarkers of inflammation among healthy women.     

MicroRNA alterations and associated aberrant DNA methylation patterns across multiple sample types in oral squamous cell carcinoma

Background

MicroRNA (miRNA) expression is broadly altered in cancer, but few studies have investigated miRNA deregulation in oral squamous cell carcinoma (OSCC). Epigenetic mechanisms are involved in the regulation of >30 miRNA genes in a range of tissues, and we aimed to investigate this further in OSCC.

Methods

TaqMan® qRT-PCR arrays and individual assays were used to profile miRNA expression in a panel of 25 tumors with matched adjacent tissues from patients with OSCC, and 8 control paired oral stroma and epithelium from healthy volunteers. Associated DNA methylation changes of candidate epigenetically deregulated miRNA genes were measured in the same samples using the MassArray® mass spectrometry platform. MiRNA expression and DNA methylation changes were also investigated in FACS sorted CD44^high oral cancer stem cells from primary tumor samples (CSCs), and in oral rinse and saliva from 15 OSCC patients and 7 healthy volunteers.

Results

MiRNA expression patterns were consistent in healthy oral epithelium and stroma, but broadly altered in both tumor and adjacent tissue from OSCC patients. MiR-375 is repressed and miR-127 activated in OSCC, and we confirm previous reports of miR-137 hypermethylation in oral cancer. The miR-200 s/miR-205 were epigenetically activated in tumors vs normal tissues, but repressed in the absence of DNA hypermethylation specifically in CD44^high oral CSCs. Aberrant miR-375 and miR-200a expression and miR-200c-141 methylation could be detected in and distinguish OSCC patient oral rinse and saliva from healthy volunteers, suggesting a potential clinical application for OSCC specific miRNA signatures in oral fluids.

Conclusions

MiRNA expression and DNA methylation changes are a common event in OSCC, and we suggest miR-375, miR-127, miR-137, the miR-200 family and miR-205 as promising candidates for future investigations. Although overall activated in OSCC, miR-200/miR-205 suppression in oral CSCs indicate that cell specific silencing of these miRNAs may drive tumor expansion and progression.     

Familial adenomatous polyposis-associated desmoids display significantly more genetic changes than sporadic desmoids

Desmoid tumours (also called deep or aggressive fibromatoses) are potentially life-threatening fibromatous lesions. Hereditary desmoid tumours arise in individuals affected by either familial adenomatous polyposis (FAP) or hereditary desmoid disease (HDD) carrying germline mutations in APC. Most sporadic desmoids carry somatic mutations in CTNNB1. Previous studies identified losses on 5q and 6q, and gains on 8q and 20q as recurrent genetic changes in desmoids. However, virtually all genetic changes were derived from sporadic tumours. To investigate the somatic alterations in FAP-associated desmoids and to compare them with changes occurring in sporadic tumours, we analysed 17 FAP-associated and 38 sporadic desmoids by array comparative genomic hybridisation and multiple ligation-dependent probe amplification. Overall, the desmoids displayed only a limited number of genetic changes, occurring in 44% of cases. Recurrent gains at 8q (7%) and 20q (5%) were almost exclusively found in sporadic tumours. Recurrent losses were observed for a 700 kb region at 5q22.2, comprising the APC gene (11%), a 2 Mb region at 6p21.2-p21.1 (15%), and a relatively large region at 6q15-q23.3 (20%). The FAP-associated desmoids displayed a significantly higher frequency of copy number abnormalities (59%) than the sporadic tumours (37%). As predicted by the APC germline mutations among these patients, a high percentage (29%) of FAP-associated desmoids showed loss of the APC region at 5q22.2, which was infrequently (3%) seen among sporadic tumours. Our data suggest that loss of region 6q15-q16.2 is an important event in FAP-associated as well as sporadic desmoids, most likely of relevance for desmoid tumour progression.     

Diet restriction and life history trade-offs in short- and long-lived species of Daphnia

The life-extending effects of diet restriction are well documented. One evolutionary model that accounts for this widespread conservation is the resource allocation model, where the selected individuals are those that can delay reproduction during periods of resource limitation. In this study, we use closely related species of a model organism, Daphnia, with widely divergent lifespans to address the relationship between diet restriction and longevity and assess whether the relationships are owing to trade-offs between reproductive and somatic investment. Specifically, we conducted a common garden experiment and constructed reaction norms for lifespan, fecundity, and body size as a function of food concentration. Our study provides evidence that the short-lived species in our study, D. pulex, shows the classically observed relationship of enhanced lifespan in response to reduced diet intake, but does not divert resources to somatic maintenance at the expense of reproduction during chronic diet restriction. In contrast, we find no evidence that the long-lived species in our study, D. pulicaria, gains any life-extending effects through diet restriction. Combined, our results provide evidence that the resource allocation model is not sufficient to explain the evolution of diet-mediated lifespan plasticity.     

Man and the last great wilderness: human impact on the deep sea

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life--SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO(2) and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO(2) and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods.     

Biogeographical patterns of marine larval trematode parasites in two intermediate snail hosts in Europe

Aim We used published inventories of trematodes in Littorina littorea (L.) and Hydrobia ulvae (Pennant) in European seas to search for two basic biogeographical patterns in the spatial occurrence of various trematode species: (1) do parasite distribution and richness patterns in the two host snails overlap with known ecoregions of free‐living organisms; and (2) does trematode species richness in the snails follow latitudinal or longitudinal gradients? Location North East Atlantic. Methods We used multidimensional scaling (MDS), analysis of similarity (ANOSIM) and analysis of variance (ANOVA) to test whether there were overlaps of parasite distribution and richness with known ecoregions of free‐living organisms. In addition, we used linear regression analyses to test whether trematode richness in snails (corrected for sampling effort) was correlated with the latitude or longitude of the sampling sites. Results When corrected for sampling effort, mean trematode species richness per site did not differ among the different ecoregions in L. littorea. In contrast, in H. ulvae, mean species richness was much lower for sites from the Celtic Sea compared with sites from the Baltic Sea and the North Sea. Based on the results of MDS analyses, trematode species composition was distinct among ecoregions; in particular, communities from the Baltic Sea differed markedly from communities in the Celtic Sea, for both snail species. Latitude and longitude were not significantly correlated with parasite species richness in either snail species. Most trematode species had restricted distributions, and only three species in L. littorea and five species in H. ulvae occurred at more than 50% of the sites. Main conclusions There is more structure in the large‐scale distribution of trematodes in gastropods than one would expect from the large‐scale dispersal capabilities of their bird and fish final hosts. We propose mechanisms based both on limited dispersal via fish and bird final hosts and on gradients in environmental factors to explain the observed patterns.     

The hot hand phenomenon as a cognitive adaptation to clumped resources

The hot hand phenomenon refers to the expectation of “streaks” in sequences of hits and misses whose probabilities are, in fact, independent (e.g., coin tosses, basketball shots). Here we propose that the hot hand phenomenon reflects an evolved psychological assumption that items in the world come in clumps, and that hot hand, not randomness, is our evolved psychological default. In two experiments, American undergraduates and Shuar hunter–horticulturalists participated in computer tasks in which they predicted hits and misses in foraging for fruits, coin tosses, and several other kinds of resources whose distributions were generated randomly. Subjects in both populations exhibited the hot hand assumption across all the resource types. The only exception was for American students predicting coin tosses where hot hand was reduced. These data suggest that hot hand is our evolved psychological default, which can be reduced (though not eliminated) by experience with genuinely independent random phenomena like coin tosses.