Data storage and data re-use in taxonomy—the need for improved storage and accessibility of heterogeneous data

The ability to rapidly generate and share molecular, visual, and acoustic data, and to compare them with existing information, and thereby to detect and na     

Regulation of oocyte and cumulus cell interactions by intermedin/adrenomedullin 2

Ovarian folliculogenesis has been studied as a model of hormonal regulation of development and differentiation, cell death, and cell-cell communication. In addition to gonadotropins from the pituitary and follicular paracrine factors, oocyte secreted factors have been shown to play critical roles in the regulation of follicular cell functions. Except for the well characterized BMP family proteins, including GDF9 and BMP15, oocytes are known to secrete oocyte secreted factors that are important for the regulation of cumulus cell survival and the maintenance of tertiary structure of cumulus cell-enclosed oocyte complexes (COCs). Based on genomic screening and studies of COCs cultured in vitro, we showed that intermedin (IMD)/adrenomedullin 2 (ADM2) is a novel oocyte-derived ligand important for the regulation of cell interactions in COCs that functions, in part, by suppressing cumulus cell apoptosis. Consistently, we showed that suppression of IMD/ADM2 signaling in growing rat ovaries in vivo leads to oocyte atresia and aberrant cell cycle progression in follicular cells. Together, our studies indicated that mammalian oocytes deploy a G protein-coupled receptor ligand to coordinate normal interactions of oocytes and cumulus cells and provided a better understanding of how the tertiary structure of a COC is maintained as follicles undergo exponential growth during the late stages of folliculogenesis.     

Time course of vascular arginase expression and activity in spontaneously hypertensive rats

There is growing evidence that vascular arginase plays a role in pathophysiology of vascular diseases. We recently reported high arginase activity/expression in young adult hypertensive spontaneously hypertensive rats (SHR). The aim of the present study was to characterize the time course of arginase pathway abnormalities in SHR and to explore the contributing role of hemodynamics and inflammation. Experiments were conducted on 5, 10, 19 and 26-week-old SHR and their age-matched control Wistar Kyoto (WKY) rats. Arginase activity as well as expression of arginase I, arginase II, endothelial and inducible NOS were determined in aortic tissue extracts. Levels of L-arginine, NO catabolites and IL-6 (a marker of inflammation) were measured in plasma. Arginase activity/expression was also measured in 10-week-old SHR previously treated with hydralazine (20 mg/kg/day, per os, for 5 weeks). As compared to WKY, SHR exhibited high vascular arginase I and II expression from prehypertensive to established stages of hypertension. However, a mismatch between expression and activity was observed at the prehypertensive stage. Arginase expression was not related either to plasma IL-6 levels or to expression of NOS. Prevention of hypertension by hydralazine significantly blunted arginase upregulation and restored arginase activity. Importantly, arginase activity and blood pressure (BP) correlated in SHR. In conclusion, our results demonstrate that arginase upregulation precedes blood pressure rising and identify elevated blood pressure as a contributing factor of arginase dysregulation in genetic hypertension. They also demonstrated a close relationship between arginase activity and BP, thus making arginase a promising target for antihypertensive therapy.     

Within-population variation in prevalence and lineage distribution of avian malaria in blue tits, Cyanistes caeruleus

The development of molecular genetic screening techniques for avian blood parasites has revealed many novel aspects of their ecology, including greatly elevated diversity and complex host-parasite relationships. Many previous studies of malaria in birds have treated single study populations as spatially homogeneous with respect to the likelihood of transmission of malaria to hosts, and we have very little idea whether any spatial heterogeneity influences different malaria lineages similarly. Here, we report an analysis of variation in the prevalence and cytochrome b lineage distribution of avian malaria infection with respect to environmental and host factors, and their interactions, in a single blue tit (Cyanistes caeruleus) population. Of 11 Plasmodium and Haemoproteus cytochrome b lineages found in 997 breeding individuals, the three most numerous (pSGS1, pTURDUS1 and pBT7) were considered separately, in addition to analyses of all avian malaria lineages pooled. Our analyses revealed marked spatial differences in the prevalence and distribution of these lineages, with local prevalence of malaria within the population ranging from over 60% to less than 10%. In addition, we found several more complex patterns of prevalence with respect to local landscape features, host state, parasite genotype, and their interactions. We discuss the implications of such heterogeneity in parasite infection at a local scale for the study of the ecology and evolution of infectious diseases in natural populations. The increased resolution afforded by the combination of molecular genetic and geographical information systems (GIS) tools has the potential to provide many insights into the epidemiology, evolution and ecology of these parasites in the future.     

Widespread Disruption of Functional Brain Organization in Early-Onset Alzheimer’s Disease

Early-onset Alzheimer’s disease (AD) patients present a different clinical profile than late-onset AD patients. This can be partially explained by cortical atrophy, although brain organization might provide more insight. The aim of this study was to examine functional connectivity in early-onset and late-onset AD patients. Resting-state fMRI scans of 20 early-onset (<65 years old), 28 late-onset (≥65 years old) AD patients and 15 “young” (<65 years old) and 31 “old” (≥65 years old) age-matched controls were available. Resting-state network-masks were used to create subject-specific maps. Group differences were examined using a non-parametric permutation test, accounting for gray-matter. Performance on five cognitive domains were used in a correlation analysis with functional connectivity in AD patients. Functional connectivity was not different in any of the RSNs when comparing the two control groups (young vs. old controls), which implies that there is no general effect of aging on functional connectivity. Functional connectivity in early-onset AD was lower in all networks compared to age-matched controls, where late-onset AD showed lower functional connectivity in the default-mode network. Functional connectivity was lower in early-onset compared to late-onset AD in auditory-, sensory-motor, dorsal-visual systems and the default mode network. Across patients, an association of functional connectivity of the default mode network was found with visuoconstruction. Functional connectivity of the right dorsal visual system was associated with attention across patients. In late-onset AD patients alone, higher functional connectivity of the sensory-motor system was associated with poorer memory performance. Functional brain organization was more widely disrupted in early-onset AD when compared to late-onset AD. This could possibly explain different clinical profiles, although more research into the relationship of functional connectivity and cognitive performance is needed.     

Neural crest invasion is a spatially-ordered progression into the head with higher cell proliferation at the migratory front as revealed by the photoactivatable protein, KikGR

Neural crest cell (NCC) invasion is a complex sculpting of individual cells into organized migratory streams that lead to organ development along the vertebrate axis. Key to our understanding of how molecular mechanisms modulate the NCC migratory pattern is information about cell behaviors, yet it has been challenging to selectively mark and analyze migratory NCCs in a living embryo. Here, we apply an innovative in vivo strategy to investigate chick NCC behaviors within the rhombomere 4 (r4) migratory stream by combining photoactivation of KikGR and confocal time-lapse analysis of H2B-mRFP1 transfected NCCs. We find that the spatial order of r4 NCC emergence translates into a distal-to-proximal invasion of the 2nd branchial arch. Lead and trailing NCCs display similar average cell speeds and directionalities. Surprisingly, we find that lead NCCs proliferate along the migratory route and grow to outnumber trailing NCCs by nearly 3 to 1. A simple, cell-based computational model reproduces the r4 NCC migratory pattern and predicts the invasion order can be disrupted by slower, less directional lead cells or by environmental noise. Our results suggest a model in which NCC behaviors maintain a spatially-ordered invasion of the branchial arches with differences in cell proliferation between the migratory front and trailing NCCs.     

Patterns of Land Cover Change in and Around Madidi National Park, Bolivia

This study examines how human land uses and biophysical factors serve as predictors of land cover change in and around Madidi National Park in Bolivia. The Greater Madidi Landscape ranges over an elevational gradient from < 200 m in the Amazon basin to 6000 m in the high Andes, contains more than ten major ecosystem types, and several protected areas and sustainable use zones. In this study, Landsat Thematic Mapper satellite images collected over the study area at the beginning of the 1990s and then the 2000s were classified according to broad land cover types. Below elevations of 3000 m, the landscape experienced equal rates of deforestation and secondary forest increases of approximately 0.63 percent annually, resulting in no significant net change. Below elevations of 1000 m, however, we found an annual net loss in forest cover of 0.11 percent. Across the landscape, land cover change was most likely to occur near areas previously deforested, near roads and population centers, and at low elevations. We found net deforestation rates to be inversely related to strength of natural resource protection laws in protected areas and other jurisdictions. Results suggest little net change for the landscape as a whole, but that local scale changes may be significant, particularly near roads. Management policies favorable for biodiversity conservation in this landscape should limit the building of new roads and immigration to biologically sensitive areas and continue to support protected areas, which are achieving a positive result for forest conservation.     

GPCR genes are preferentially retained after whole genome duplication

One of the most interesting questions in biology is whether certain pathways have been favored during evolution, and if so, what properties could cause such a preference. Due to the lack of experimental evidence, whether select gene families have been preferentially retained over time after duplication in metazoan organisms remains unclear. Here, by syntenic mapping of nonchemosensory G protein-coupled receptor genes (nGPCRs which represent half the receptome for transmembrane signaling) in the vertebrate genomes, we found that, as opposed to the 8-15% retention rate for whole genome duplication (WGD)-derived gene duplicates in the entire genome of pufferfish, greater than 27.8% of WGD-derived nGPCRs which interact with a nonpeptide ligand were retained after WGD in pufferfish Tetraodon nigroviridis. In addition, we show that concurrent duplication of cognate ligand genes by WGD could impose selection of nGPCRs that interact with a polypeptide ligand. Against less than 2.25% probability for parallel retention of a pair of WGD-derived ligands and a pair of cognate receptor duplicates, we found a more than 8.9% retention of WGD-derived ligand-nGPCR pairs--threefold greater than one would surmise. These results demonstrate that gene retention is not uniform after WGD in vertebrates, and suggest a Darwinian selection of GPCR-mediated intercellular communication in metazoan organisms.