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| | 1. |
2011 Feb 4 |
Extracts of Canadian First Nations Medicinal Plants, Used as Natural Products, Inhibit Neisseria gonorrhoeae Isolates With Different Antibiotic Resistance Profiles.
Cybulska P, Thakur SD, Foster BC, Scott IM, Leduc RI, Arnason JT, Dillon JA
Sex Transm Dis. 2011 Feb 4; [Epub ahead of print]
Abstract
BACKGROUND:: Neisseria gonorrhoeae (Ng) has developed resistance to most antimicrobial agents and the antibiotics recommended for therapy are restricted, for the most part, to third generation cephalosporins. In order to investigate new potential sources of antimicrobial agents, the antibacterial properties of 14 Canadian plants used in traditional First Nations' medicine were tested against Ng isolates having differing antimicrobial susceptibility profiles. METHODS:: Ethanolic extracts of 14 Canadian botanicals, analyzed by high-performance liquid chromatography, were tested for their antimicrobial activity (disc diffusion and/or agar dilution assays) against susceptible Ng reference strains and a panel of 28 Ng isolates with various antimicrobial resistance profiles. RESULTS:: Extracts of Arctostaphylos uva ursi (kinnikinnick or bearberry), Hydrastis canadensis (goldenseal), Prunus serotina (black cherry), and Rhodiola rosea (roseroot) inhibited the growth of all Ng isolates with minimum inhibitory concentrations of 32 μg/mL, 4 to 32 μg/mL, 16 to >32 μg/mL, and 32 to 64 μg/mL, respectively. Extracts of Acorus americanus (sweet flag), Berberis vulgaris (barberry), Cimicifuga racemosa (black cohosh), Equisetum arvense (field horsetail), Gaultheria procumbens (wintergreen), Ledum groenlandicum (Labrador tea), Ledum palustre (marsh Labrador tea), Oenothera biennis (common evening primrose), Sambucus nigra (elderberry), and Zanthoxylum americanum (prickly ash) had weak or no antimicrobial activity against the Ng isolates with minimum inhibitory concentrations ≥256 μg/mL. The phytochemical berberine from H. canadensis inhibited the growth of all Ng isolates. The phytochemicals, salidroside and rosavin, present in R. rosea, also showed inhibitory activity against Ng strains. CONCLUSION:: Canadian botanicals represent a potential source of novel compounds which inhibit Ng, including isolates resistant to antibiotics.
[Pubmed: 21301385]
| | 2. |
2011 Jan 08 |
Lyophilized silk fibroin hydrogels for the sustained local delivery of therapeutic monoclonal antibodies.
Guziewicz N, Best A, Perez-Ramirez B, Kaplan DL
Biomaterials. 2011 Apr;32(10):2642-50. Epub 2011 Jan 08.
Abstract
The development of sustained delivery systems compatible with protein therapeutics continues to be a significant unmet need. A lyophilized silk fibroin hydrogel matrix (lyogel) for the sustained release of pharmaceutically relevant monoclonal antibodies is described. Sonication of silk fibroin prior to antibody incorporation avoids exposing the antibody to the sol-gel transition inducing shear stress. Fourier Transform Infrared (FTIR) analysis showed no change in silk structural composition between hydrogel and lyogel or with increasing silk fibroin concentration. Antibody release from hydrogels occurred rapidly over 10 days regardless of silk concentration. Upon lyophilization, sustained antibody release was observed over 38 days from lyogels containing 6.2% (w/w) silk fibroin and above. In 3.2% (w/w) silk lyogels, antibody release was comparable to hydrogels. Swelling properties of lyogels followed a similar threshold behavior. Lyogels at 3.2% (w/w) silk recovered approximately 90% of their fluid mass upon rehydration, while approximately 50% fluid recovery was observed at 6.2% (w/w) silk and above. Antibody release was primarily governed by hydrophobic/hydrophilic silk-antibody interactions and secondarily altered by the hydration resistance of the lyogel. Hydration resistance was controlled by altering β-sheet (crystalline) density of the matrix. The antibody released from lyogels maintained biological activity. Silk lyogels offer an advantage as a delivery matrix over other hydrogel materials for the slow release of the loaded protein, making lyogels suitable for long-term sustained release applications.
[Pubmed: 21216004]
| | 3. |
2011 Feb 15 |
HPTLC densitometric analysis of arbutin in bulk drug and methanolic extracts of Arctostaphylos uva-ursi.
Alam P, Alqasoumi SI, Shakeel F, Abdel-Kader MS
Nat Prod Res. 2011 Feb 15;:1-5. Epub 2011 Feb 15.
Abstract
A high-performance thin layer chromatographic densitometric method for the analysis of arbutin was developed and validated in the present investigation. Arbutin was separated on aluminium-backed silica gel 60 F(254) plates with methanol : chloroform (3 : 7)% (v/v) as the mobile phase. This system was found to give a compact spot of arbutin at a retention factor (R(f)) value of 0.32 ± 0.02. The limit of detection and limit of quantification were found to be 35.42 and 106.26 ng/spot, respectively. The proposed method with a high degree of precision and accuracy was employed for the analysis of arbutin in the bulk drug and methanolic extract of Arctostaphylos uva-ursi.
[Pubmed: 21331974]
| | 4. |
2011 Feb 08 |
Root fungal symbionts interact with mammalian herbivory, soil nutrient availability and specific habitat conditions.
Ruotsalainen AL, Eskelinen A
Oecologia. 2011 Jul;166(3):807-17. Epub 2011 Feb 08.
Abstract
Herbivory, competition and soil fertility interactively shape plant communities and exhibit an important role in modifying conditions for host-dependent fungal symbionts. However, field studies on the combined impacts of natural herbivory, competition and soil fertility on root fungal symbionts are rare. We asked how mammalian herbivory, fertilization, liming and plant-plant competition affect the root colonization of arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi of the dicot herb, Solidago virgaurea. The 2-year full-factorial experiment was conducted in two contrasting habitats: non-acidic and acidic mountain tundra. We found that herbivory increased arbuscular colonization (i.e. the site of resource exchange) at fertile non-acidic sites, where vegetation was rich in species having AMF symbionts, whereas at infertile acidic sites, where plants having AMF symbiont are scarce, the response was the opposite. Herbivory of the host plant negatively affected DSE hyphal and sclerotial colonization in unfertilized plots, possibly due to reduced carbon flow from the host plant while there was no effect of herbivory in fertilized plots. DSE colonization was highest in unfertilized exclosures where soil nutrient concentrations were also lowest. Liming had a negative effect on DSE hyphal colonization, and its effect also interacted with herbivory and the habitat. Biomass removal of the neighboring plants did not affect the root colonization percent of either arbuscules or DSE. Our results show that the impacts of aboveground mammalian herbivory, soil nutrient availability and specific habitat conditions on belowground root fungal symbionts are highly dependent on each other. Arbuscule response to herbivory appeared to be regulated by specific habitat conditions possibly caused by differences in the AMF availability in the soil while DSE response was associated with availability of host-derived carbon. Our result of the relationship between herbivory and soil nutrients suggests an important role of DSE in ecosystem processes.
[Pubmed: 21301877]
| | 5. |
2011 May 26 |
Multiple congenital ocular anomalies in Icelandic horses
Andersson, Axelsson, Dubielzig, Lindgren, Ekesten
BMC Vet Res 2011 May 26;7:21. published online before print
Abstract
Multiple congenital ocular anomalies (MCOA) syndrome is a hereditary congenital eye defect that was first described in Silver colored Rocky Mountain horses. The mutation causing this disease is located within a defined chromosomal interval, which also contains the gene and mutation that is associated with the Silver coat color (PMEL17, exon 11). Horses that are homozygous for the disease-causing allele have multiple defects (MCOA-phenotype), whilst the heterozygous horses predominantly have cysts of the iris, ciliary body or retina (Cyst-phenotype). It has been argued that these ocular defects are caused by a recent mutation that is restricted to horses that are related to the Rocky Mountain Horse breed. For that reason we have examined another horse breed, the Icelandic horse, which is historically quite divergent from Rocky Mountain horses.
[Pubmed: 21615885]
| | 6. |
2011 Jun |
Targeted analysis of four breeds narrows equine Multiple Congenital Ocular Anomalies locus to 208 kilobases
Andersson, Lyberg, Cothran, Ramsey, Juras, Mikko, Ekesten, Ewart, Lindgren
Mamm Genome 2011 Jun;22(5-6):353-360.
Abstract
The syndrome Multiple Congenital Ocular Anomalies (MCOA) is the collective name ascribed to heritable congenital eye defects in horses. Individuals homozygous for the disease allele (MCOA phenotype) have a wide range of eye anomalies, while heterozygous horses (Cyst phenotype) predominantly have cysts that originate from the temporal ciliary body, iris, and/or peripheral retina. MCOA syndrome is highly prevalent in the Rocky Mountain Horse but the disease is not limited to this breed. Affected horses most often have a Silver coat color; however, a pleiotropic link between these phenotypes is yet to be proven. Locating and possibly isolating these traits would provide invaluable knowledge to scientists and breeders. This would favor maintenance of a desirable coat color while addressing the health concerns of the affected breeds, and would also provide insight into the genetic basis of the disease. Identical-by-descent mapping was used to narrow the previous 4.6-Mb region to a 264-kb interval for the MCOA locus. One haplotype common to four breeds showed complete association to the disease (Cyst phenotype, n = 246; MCOA phenotype, n = 83). Candidate genes from the interval, SMARCC2 and IKZF4, were screened for polymorphisms and genotyped, and segregation analysis allowed the MCOA syndrome region to be shortened to 208 kb. This interval also harbors PMEL17, the gene causative for Silver coat color. However, by shortening the MCOA locus by a factor of 20, 176 other genes have been unlinked from the disease and only 15 genes remain.
[Pubmed: 21465164]
| | 7. |
2011 Jul |
Nutrient composition, phenolic content and free radical scavenging activity of some uncommon vegetables of Pakistan.
Khattak KF
Pak J Pharm Sci. 2011 Jul;24(3):277-83.
Abstract
Vegetables play a vital role in the prevention of human disease and in the improvement of general health as these contain vitamins, amino acids, fiber, antioxidants and minerals. In the present study, some less familiar vegetables of Pakistan namely chickpea (leaves), chungah (shoots), drumstick tree (inflorescences), radish (fruit pods), mountain ebony (flower buds), mustard (leaves), purslane (leaves) and white goosefoot (leaves and shoots) were evaluated for proximate composition, mineral content, phenolic content and free radical scavenging activity. The protein, fat, fiber, carbohydrate and ash contents of the selected vegetables were in the range of 2.9 to 6.6%, 0.2 to 2.5%, 2.4 to 8.6%, 9.7 to 20.1% and 1.0 to 2.3%, respectively. The concentration of vitamin C ranged between 32.6 to 120.1 mg/100 g. The phosphorus, calcium, iron, zinc, manganese, magnesium and copper were 190 to 3400, 103 to 987, 19 to 93, 12 to 47, 9 to 121, 299 to 1635 and non detectable level to 42 mg/kg, respectively. The amount of total phenolic content varied from 55.3 to 221.0 mg/g in the dry methanolic extracts of the studied plants. The EC(50) values were below 1400 μg/ml, indicating that all the studied vegetables have good scavenging effect on DPPH radical.
[Pubmed: 21715260]
| | 8. |
2011 Jul 29 |
Litter sex composition affects life-history traits in yellow-bellied marmots.
Monclús R, Blumstein DT
J Anim Ecol. 2011 Jul 29; [Epub ahead of print]
Abstract
1. The presence of siblings might have long-lasting fitness consequences because they influence the early environment in which an animal develops. Several studies under laboratory conditions have shown long-lasting consequences from the presence of male siblings in utero on morphology and life-history traits. However, in wild animals, such effects of litter sex composition are unexplored. 2. We capitalized on a long-term study of individually marked yellow-bellied marmots (Marmota flaviventris) and documented the effects of weaned litter sex composition and anogenital distance on several life-history and fitness traits. 3. First, we demonstrated that the number of males in a litter influenced anogenital distance. Then, we found that masculinized females, those with larger anogenital distances, were less likely to survive their first hibernation, were more likely to disperse and were less likely to become pregnant and wean young. Males from male-biased litters had lower growth rates, but we failed to detect longer-term consequences. 4. Taken together, our results show profound sex-dependent effects of litter sex composition, probably due to differential prenatal exposure to androgens, in free-living animals. We conclude that masculinization might constitute an alternative mechanism explaining variation in different demographic traits. This finding highlights the importance of studying these maternal effects, and they enhance our concern over the widespread use of endocrine disrupting compounds.
[Pubmed: 21801175]
| | 9. |
2011 May |
Growth, fire history, and browsing recorded in wood rings of shrubs in a mild temperate climate.
Coale TH, Deveny AJ, Fox LR
Ecology. 2011 May;92(5):1020-6.
Abstract
Separate effects of abiotic and biotic factors on the structure and dynamics of ecological communities may be recorded in growth rings of woody plants. We used Ceanothus cuneatus rigidus and Arctostaphylos pumila to tease apart the roles of fire, rain, and herbivores on the histories and community structure of four areas in a coastal mediterranean-type climate in central California with mild winters and mild summers. Ring widths of both species were related to rainfall in two of the areas; heavy deer browsing on Ceanothus overwhelmed the climate signal in the others. Ceanothus germination was more closely related to heavy rainfall, especially during ENSO years, than to fire events. In a related greenhouse experiment that evaluated these observations, the same proportions of new Ceanothus seeds germinated after burning and after receiving regular water for several months, but germination of old seeds responded primarily to the fire treatment. In areas where heavy browsing by mammals reduces recruitment and growth of Ceanothus and increases mortality, the continuance of the Ceanothus population must rely heavily on germination from the persistent seed bank during unusually wet years or after occasional fires. Because Arctostaphylos can produce new stems from underground roots, individual plants may survive and produce seeds until another fire.
[Pubmed: 21661563]
| | 10. |
2011 May 3 |
An Atropa Belladonna L. poisoning with acute subdural hematoma.
Cikla U, Turkmen S, Karaca Y, Ayaz AF, Turedi S, Gunduz A
Hum Exp Toxicol. 2011 May 3; [Epub ahead of print]
Abstract
Atropa belladonna L. is a plant long known to cause poisoning. But no cases of acute subdural hematoma resulting from such poisoning have been reported so far. Care must also be taken in terms of acute pancreatitis and rhabdomyolysis in cases of such poisoning. The plant may sometimes be mistaken for the Caucasian blueberry, V. arctostaphylos L. At least one anti-cholinesterase toxidrome finding was determined in all the nine cases of belladonna poisoning in this series. No elevated creatine kinase was reported in one case with acute subdural hematoma and hyperamylasemia.
[Pubmed: 21540312]
| | 11. |
2011 Aug |
Comparison of Agroforests and Protected Forests in the East Usambara Mountains, Tanzania
Hall, Gillespie, Mwangoka
Environ Manage 2011 Aug;48(2):237-247.
Abstract
Comparative studies on plant species richness, endemism, floristic composition, and structure between protected and unprotected forests are few in the Eastern Arc Mountains, one of the most biodiverse ecosystems in Africa. This study from one mountain range, the East Usambaras, examines floristic and structural tree data from 41–0.5 ha plots in four types of Eastern Arc forest: active agroforests, recently abandoned agroforests, mature secondary forest, and natural forest. Active agroforests had significantly lower tree species richness, endemic species richness, and stand density compared to natural and mature secondary forest. Recently abandoned agroforests contained a higher tree species richness, density, and tree height than active agroforests. Active and abandoned agroforests were dominated by an invasive tree, Maesopsis eminii. This tree species makes up a large percentage of the stems in active agroforests (26%), recently abandoned agroforests (32%), and in the canopy of mature secondary forests ∼ 30 years post logging (30%). Through time the increasing dominance of this non-native tree in active agroforests is a concern when considering the role of agroforests in a landscape scale conservation strategy.
[Pubmed: 21079957]
| | 12. |
2011 Jul 1 |
Characterisation of acid mine drainage in a high rainfall mountain environment, New Zealand.
Davies H, Weber P, Lindsay P, Craw D, Pope J
Sci. Total Environ. 2011 Jul 1;409(15):2971-80.
Abstract
The Stockton coal mine lies at 700-1100 m above sea level in a mountainous orographic precipitation zone on the West Coast of the South Island of New Zealand. Rainfall exceeds 6000 mm/year and arrives with frequent flood events that can deliver > 200 mm/day. Streams vary in discharges by up to two orders of magnitude over a time scale of hours. Pyritic waste rock at the mine interacts chemically with even the most intense rainfall, and almost all runoff is acidic to some degree. In the most intense rain event recorded in this study (> 10 mm/hour), dilution of acid mine drainage (AMD) occurred and pH rose from 3 to >5 over several hours, with stream discharge at a monitoring point rising from <0.5 to >100 cumecs. However, most rain events of similar magnitude are less intense, longer duration, and only raise AMD pH to ~4 with similar high discharges. Results presented here for Stockton confirm that it is the intensity of rain events on the hourly scale, rather than the total amount of rainwater delivered to the site, that governs the amount and composition of AMD generated during flood events. Stream discharge loads of dissolved iron and aluminium range from ~20 to 1000 kg/hour. Dissolved sulfate and acidity loads are typically ~500 kg/hour but can exceed 20 tonnes/hour in rain events. First flush effects observable elsewhere around the world involving peak metal loads following dry periods or seasonal changes are not obvious at Stockton due to the high and variable rainfall environment. Dissolved Fe concentrations may be limited in runoff waters by precipitation of jarosite and schwertmannite, especially when rainfall is sufficiently intense to raise pH to 4 or higher. These minerals are widespread in the exposed waste rock on site. Likewise, precipitation of alunite may occur as pH rises in rain events, but no field evidence for this has been observed.
[Pubmed: 21669330]
| | 13. |
2011 Oct 27 |
Niche differentiation of two sympatric species of Microdochium colonizing the roots of common reed.
Ernst M, Neubert K, Mendgen KW, Wirsel SG
BMC Microbiol. 2011 Oct 27;11(1):242. Epub 2011 Oct 27.
Abstract
ABSTRACT: BACKGROUND: Fungal endophyte communities are often comprised of many species colonizing the same host. However, little is known about the causes of this diversity. On the one hand, the apparent coexistence of closely related species may be explained by the traditional niche differentiation hypothesis, which suggests that abiotic and/or biotic factors mediate partitioning. For endophytes, such factors are difficult to identify, and are therefore in most cases unknown. On the other hand, there is the neutral hypothesis, which suggests that stochastic factors may explain high species diversity. There is a need to investigate to what extent each of these hypotheses may apply to endophytes. RESULTS: The niche partitioning of two closely related fungal endophytes, Microdochium bolleyi and M. phragmitis, colonizing Phragmites australis, was investigated. The occurrences of each species were assessed using specific nested-PCR assays for 251 field samples of common reed from Lake Constance, Germany. These analyses revealed niche preferences for both fungi. From three niche factors assessed, i.e. host habitat, host organ and season, host habitat significantly differentiated the two species. M. bolleyi preferred dry habitats, whereas M. phragmitis prevailed in flooded habitats. In contrast, both species exhibited a significant preference for the same host organ, i.e. roots. Likewise the third factor, season, did not significantly distinguish the two species. Differences in carbon utilization and growth temperature could not conclusively explain the niches. The inclusion of three unrelated species of Ascomycota, which also colonize P. australis at the same locations, indicated spatio-temporal niche partitioning between all fungi. None of the species exhibited the same preferences for all three factors, i.e. host habitat, host organ, and time of the season. CONCLUSIONS: The fungal species colonizing common reed investigated in this study seem to exploit niche differences leading to a separation in space and time, which may allow for their coexistence on the same host. A purely neutral model is unlikely to explain the coexistence of closely related endophytes on common reed.
[Pubmed: 22032611]
| | 14. |
2011 Nov 1 |
Correlations of cave levels, stream terraces and planation surfaces along the River Mur-Timing of landscape evolution along the eastern margin of the Alps.
Wagner T, Fritz H, Stüwe K, Nestroy O, Rodnight H, Hellstrom J, Benischke R
Geomorphology (Amst). 2011 Nov 1;134(1-2):62-78.
Abstract
The transition zone of the Eastern Alps to the Pannonian Basin provides one of the best sources of information on landscape evolution of the Eastern Alpine mountain range. The region was non-glaciated during the entire Pleistocene. Thus, direct influence of glacial carving as a landscape forming process can be excluded and relics of landforms are preserved that date back to at least the Late Neogene. In this study, we provide a correlation between various planation surfaces across the orogen-basin transition. In particular, we use stream terraces, planation surfaces and cave levels that cover a vertical spread of some 700 m. Our correlation is used to show that both sides of the transition zone uplifted together starting at least about 5 Ma ago. For our correlation we use recently published terrestrial cosmogenic nuclide (TCN) burial ages from cave sediments, new optically stimulated luminescence (OSL) ages of a stream terrace and U-Th ages from speleothems. Minimum age constraints of cave levels from burial ages of cave sediments covering the last ~ 4 Ma are used to place age constraints on surface features by parallelizing cave levels with planation surfaces. The OSL results for the top section of the type locality of the Helfbrunn terrace suggest an Early Würm development (80.5 ± 3.7 to 68.7 ± 4.0 ka). The terrace origin as a penultimate gravel deposit (in classical Alpine terminology Riss) is therefore questioned. U-series speleothem ages from caves nearby indicate formation during Marine Isotope Stages (MIS) 5c and 5a which are both interstadial warm periods. As OSL ages from the terrace also show a time of deposition during MIS 5a ending at the MIS 5/4 transition, this supports the idea of temperate climatic conditions at the time of deposition. In general, tectonic activity is interpreted to be the main driving force for the formation and evolution of these landforms, whilst climate change is suggested to be of minor importance. Obvious hiatuses in Miocene to Pleistocene sediments are related to ongoing erosion and re-excavation of an uplifting and rejuvenating landscape.
[Pubmed: 22053124]
| | 15. |
2011 Oct 26 |
Development of Gene Expression Markers of Acute Heat-Light Stress in Reef-Building Corals of the Genus Porites
Kenkel, Aglyamova, Alamaru, Bhagooli, Capper, Cunning, deVillers, Haslun, Hédouin, Keshavmurthy, Kuehl, Mahmoud, McGinty, Montoya-Maya, Palmer, Pantile, Sánchez, Schils, Silverstein, Squiers, Tang, Goulet, Matz
PLoS One 2011 Oct 26;6(10). published online before print
Abstract
Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide.
[Pubmed: 22046408]
| | 16. |
2011 Sep |
Subpopulation structure of caribou (Rangifer tarandus L.) in arctic and subarctic Canada.
Nagy JA, Johnson DL, Larter NC, Campbell MW, Derocher AE, Kelly A, Dumond M, Allaire D, Croft B
Ecol Appl. 2011 Sep;21(6):2334-48.
Abstract
Effective management and conservation of species, subspecies, or ecotypes require an understanding of how populations are structured in space. We used satellite-tracking locations and hierarchical and fuzzy clustering to quantify subpopulations within the behaviorally different barren-ground caribou (Rangifer tarandus groenlandicus), Dolphin and Union island caribou (R. t. groenlandicus x pearyi), and boreal (R. t. caribou) caribou ecotypes in the Northwest Territories and Nunavut, Canada. Using a novel approach, we verified that the previously recognized Cape Bathurst, Bluenose-West, Bluenose-East, Bathurst, Beverly, Qamanirjuaq, and Lorillard barren-ground subpopulations were robust and that the Queen Maude Gulf and Wager Bay barren-ground subpopulations were organized as individuals. Dolphin and Union island and boreal caribou formed one and two distinct subpopulation, respectively, and were organized as individuals. Robust subpopulations were structured by strong annual spatial affiliation among females; subpopulations organized as individuals were structured by migratory connectivity, barriers to movement, and/or habitat discontinuity. One barren-ground subpopulation used two calving grounds, and one calving ground was used by two barren-ground subpopulations, indicating that these caribou cannot be reliably assigned to subpopulations solely by calving-ground use. They should be classified by annual spatial affiliation among females. Annual-range size and path lengths varied significantly among ecotypes, including mountain woodland caribou (R. t. caribou), and reflected behavioral differences. An east-west cline in annual-range sizes and path lengths among migratory barren-ground subpopulations likely reflected differences in subpopulation size and habitat conditions and further supported the subpopulation structure identified.
[Pubmed: 21939065]
| | 17. |
2011 Nov 14 |
Cesium-137 deposition and contamination of Japanese soils due to the Fukushima nuclear accident.
Yasunari TJ, Stohl A, Hayano RS, Burkhart JF, Eckhardt S, Yasunari T
Proc Natl Acad Sci U S A. 2011 Nov 14; [Epub ahead of print]
Abstract
The largest concern on the cesium-137 ((137)Cs) deposition and its soil contamination due to the emission from the Fukushima Daiichi Nuclear Power Plant (NPP) showed up after a massive quake on March 11, 2011. Cesium-137 ((137)Cs) with a half-life of 30.1 y causes the largest concerns because of its deleterious effect on agriculture and stock farming, and, thus, human life for decades. Removal of (137)Cs contaminated soils or land use limitations in areas where removal is not possible is, therefore, an urgent issue. A challenge lies in the fact that estimates of (137)Cs emissions from the Fukushima NPP are extremely uncertain, therefore, the distribution of (137)Cs in the environment is poorly constrained. Here, we estimate total (137)Cs deposition by integrating daily observations of (137)Cs deposition in each prefecture in Japan with relative deposition distribution patterns from a Lagrangian particle dispersion model, FLEXPART. We show that (137)Cs strongly contaminated the soils in large areas of eastern and northeastern Japan, whereas western Japan was sheltered by mountain ranges. The soils around Fukushima NPP and neighboring prefectures have been extensively contaminated with depositions of more than 100,000 and 10,000 MBq km(-2), respectively. Total (137)Cs depositions over two domains: (i) the Japan Islands and the surrounding ocean (130-150 °E and 30-46 °N) and, (ii) the Japan Islands, were estimated to be more than 5.6 and 1.0 PBq, respectively. We hope our (137)Cs deposition maps will help to coordinate decontamination efforts and plan regulatory measures in Japan.
[Pubmed: 22084074]
| | 18. |
2011 Nov 18 |
A genetic discontinuity in root-nodulating bacteria of cultivated pea in the Indian trans-Himalayas.
Rahi P, Kapoor R, Young JP, Gulati A
Mol Ecol. 2011 Nov 18; [Epub ahead of print]
Abstract
Evolutionary relationships of 120 root-nodulating bacteria isolated from the nodules of Pisum sativum cultivated at 22 different locations of the trans-Himalayan valleys of Lahaul and Spiti in the state of Himachal Pradesh of India were studied using 16S rRNA gene PCR-RFLP, ERIC-PCR, sequencing of 16S rRNA, atpD, recA, nodC and nifH genes, carbon-source utilization pattern (BIOLOG™), and whole-cell fatty acid profiling. The results demonstrated that all isolates belonged to Rhizobium leguminosarum symbiovar viciae (Rlv). Isolates from the two valleys were clearly separated on the basis of ERIC fingerprints, carbon-source utilization pattern, and whole-cell fatty acid methyl esters. Phylogenetic analysis of atpD, recA, nodC and nifH genes revealed a common Rlv sublineage in Spiti valley. Lahaul valley isolates were represented by three sequence types of atpD and recA genes, and four sequence types of nodC and nifH genes. Genotypes from the two valleys were completely distinct, except for two Lahaul isolates that shared nodC and nifH sequences with Spiti isolates but were otherwise more similar to other Lahaul isolates. Isolates from the two highest Spiti valley sites (above 4000 m) had a distinctive whole-cell fatty acid profile. Spiti valley isolates are closely related to Rlv sublineages from Xinjiang and Shanxi provinces in China, while Lahaul valley isolates resemble cosmopolitan strains of the western world. The high mountain pass between these valleys represents a boundary between two distinct microbial populations.
[Pubmed: 22092487]
| | 19. |
2011 Nov 16 |
Bumble-bee learning selects for both early and long flowering in food-deceptive plants.
Internicola AI, Harder LD
Proc Biol Sci. 2011 Nov 16; [Epub ahead of print]
Abstract
Most rewardless orchids engage in generalized food-deception, exhibiting floral traits typical of rewarding species and exploiting the instinctive foraging of pollinators. Generalized food-deceptive (GFD) orchids compete poorly with rewarding species for pollinator services, which may be overcome by flowering early in the growing season when relatively more pollinators are naive and fewer competing plant species are flowering, and/or flowering for extended periods to enhance the chance of pollinator visits. We tested these hypotheses by manipulating flowering time and duration in a natural population of Calypso bulbosa and quantifying pollinator visitation based on pollen removal. Both early and long flowering increased bumble-bee visitation compared with late and brief flowering, respectively. To identify the cause of reduced visitation during late flowering, we tested whether negative experience with C. bulbosa (avoidance learning) and positive experience with a rewarding species, Arctostaphylos uva-ursi, (associative learning) by captive bumble-bees could reduce C. bulbosa's competitiveness. Avoidance learning explained the higher visitation of early- compared with late-flowering C. bulbosa. The resulting pollinator-mediated selection for early flowering may commonly affect GFD orchids, explaining their tendency to flower earlier than rewarding orchids. For dissimilar deceptive and rewarding sympatric species, associative learning may additionally favour early flowering by GFD species.
[Pubmed: 22090384]
| | 20. |
2011 Nov 9 |
Avian Conservation Practices Strengthen Ecosystem Services in California Vineyards
Jedlicka, Greenberg, Letourneau
PLoS One 2011 Nov 9;6(11). published online before print
Abstract
Insectivorous Western Bluebirds (Sialia mexicana) occupy vineyard nest boxes established by California winegrape growers who want to encourage avian conservation. Experimentally, the provision of available nest sites serves as an alternative to exclosure methods for isolating the potential ecosystem services provided by foraging birds. We compared the abundance and species richness of avian foragers and removal rates of sentinel prey in treatments with songbird nest boxes and controls without nest boxes. The average species richness of avian insectivores increased by over 50 percent compared to controls. Insectivorous bird density nearly quadrupled, primarily due to a tenfold increase in Western Bluebird abundance. In contrast, there was no significant difference in the abundance of omnivorous or granivorous bird species some of which opportunistically forage on grapes. In a sentinel prey experiment, 2.4 times more live beet armyworms (Spodoptera exigua) were removed in the nest box treatment than in the control. As an estimate of the maximum foraging services provided by insectivorous birds, we found that larval removal rates measured immediately below occupied boxes averaged 3.5 times greater than in the control. Consequently the presence of Western Bluebirds in vineyard nest boxes strengthened ecosystem services to winegrape growers, illustrating a benefit of agroecological conservation practices. Predator addition and sentinel prey experiments lack some disadvantages of predator exclusion experiments and were robust methodologies for detecting ecosystem services.
[Pubmed: 22096555]
| | 21. |
2011 Nov 9 |
Noise Pollution Filters Bird Communities Based on Vocal Frequency
Francis, Ortega, Cruz
PLoS One 2011 Nov 9;6(11). published online before print
Abstract
Human-generated noise pollution now permeates natural habitats worldwide, presenting evolutionarily novel acoustic conditions unprecedented to most landscapes. These acoustics not only harm humans, but threaten wildlife, and especially birds, via changes to species densities, foraging behavior, reproductive success, and predator-prey interactions. Explanations for negative effects of noise on birds include disruption of acoustic communication through energetic masking, potentially forcing species that rely upon acoustic communication to abandon otherwise suitable areas. However, this hypothesis has not been adequately tested because confounding stimuli often co-vary with noise and are difficult to separate from noise exposure.
[Pubmed: 22096517]
| | 22. |
2011 Nov 2 |
MiR-223 Suppresses Cell Proliferation by Targeting IGF-1R
Jia, Li, Zhu, Dong, Fu, Zhao, Wu, Wu
PLoS One 2011 Nov 2;6(11). published online before print
Abstract
To study the roles of microRNA-223 (miR-223) in regulation of cell growth, we established a miR-223 over-expression model in HeLa cells infected with miR-223 by Lentivirus pLL3.7 system. We observed in this model that miR-223 significantly suppressed the proliferation, growth rate, colony formation of HeLa cells in vitro, and in vivo tumorigenicity or tumor formation in nude mice. To investigate the mechanisms involved, we scanned and examined the potential and putative target molecules of miR-223 by informatics, quantitative PCR and Western blot, and found that insulin-like growth factor-1 receptor (IGF-1R) was the functional target of miR-223 inhibition of cell proliferation. Targeting IGF-1R by miR-223 was not only seen in HeLa cells, but also in leukemia and hepatoma cells. The downstream pathway, Akt/mTOR/p70S6K, to which the signal was mediated by IGF-1R, was inhibited as well. The relative luciferase activity of the reporter containing wild-type 3′UTR(3′untranslated region) of IGF-1R was significantly suppressed, but the mutant not. Silence of IGF-1R expression by vector-based short hairpin RNA resulted in the similar inhibition with miR-223. Contrarily, rescued IGF-1R expression in the cells that over-expressed miR-223, reversed the inhibition caused by miR-223 via introducing IGF-1R cDNA that didn't contain the 3′UTR. Meanwhile, we also noted that miR-223 targeted Rasa1, but the downstream molecules mediated by Rasa1 was neither targeted nor regulated. Therefore we believed that IGF-1R was the functional target for miR-223 suppression of cell proliferation and its downstream PI3K/Akt/mTOR/p70S6K pathway suppressed by miR-223 was by targeting IGF-1R.
[Pubmed: 22073238]
| | 23. |
2011 Nov 18 |
The indirect consequences of a mutualism: comparing positive and negative components of the net interaction between honeydew-tending ants and host plants.
Grinath JB, Inouye BD, Underwood N, Billick I
J Anim Ecol. 2011 Nov 18; [Epub ahead of print]
Abstract
1. In ecological webs, net indirect interactions between species are composed of interactions that vary in sign and magnitude. Most studies have focused on negative component interactions (e.g. predation, herbivory) without considering the relative importance of positive interactions (e.g. mutualism, facilitation) for determining net indirect effects. 2. In plant/arthropod communities, ants have multiple top-down effects via mutualisms with honeydew-producing herbivores and harassment of and predation on other herbivores; these ant effects provide opportunities for testing the relative importance of positive and negative interspecific interactions. We manipulated the presence of ants, honeydew-producing membracids and leaf-chewing beetles on perennial host plants in field experiments in Colorado to quantify the relative strength of these different types of interactions and their impact on the ant's net indirect effect on plants. 3. In 2007, we demonstrated that ants simultaneously had a positive effect on membracids and a negative effect on beetles, resulting in less beetle damage on plants hosting the mutualism. 4. In 2008, we used structural equation modelling to describe interaction strengths through the entire insect herbivore community on plants with and without ants. The ant's mutualism with membracids was the sole strong interaction contributing to the net indirect effect of ants on plants. Predation, herbivory and facilitation were weak, and the net effect of ants reduced plant reproduction. This net indirect effect was also partially because of behavioural changes of herbivores in the presence of ants. An additional membracid manipulation showed that the membracid's effect on ant activity was largely responsible for the ant's net effect on plants; ant workers were nearly ten times as abundant on plants with mutualists, and effects on other herbivores were similar to those in the ant manipulation experiment. 5. These results demonstrate that mutualisms can be strong relative to negative direct interspecific interactions and that positive interactions deserve attention as important components of ecological webs.
[Pubmed: 22098489]
| | 24. |
2011 Apr 22 |
Effects of leaf age and tree size on stomatal and mesophyll limitations to photosynthesis in mountain beech (Nothofagus solandrii var. cliffortiodes).
Whitehead D, Barbour MM, Griffin KL, Turnbull MH, Tissue DT
Tree Physiol. 2011 Sep;31(9):985-96. Epub 2011 Apr 22.
Abstract
Mesophyll conductance, g(m), was estimated from measurements of stomatal conductance to carbon dioxide transfer, g(s), photosynthesis, A, and chlorophyll fluorescence for Year 0 (current-year) and Year 1 (1-year-old) fully sunlit leaves from short (2 m tall, 10-year-old) and tall (15 m tall, 120-year-old) Nothofagus solandrii var. cliffortiodes trees growing in adjacent stands. Rates of photosynthesis at saturating irradiance and ambient CO(2) partial pressure, A(satQ), were 25% lower and maximum rates of carboxylation, V(cmax), were 44% lower in Year 1 leaves compared with Year 0 leaves across both tree sizes. Although g(s) and g(m) were not significantly different between Year 0 and Year 1 leaves and g(s) was not significantly different between tree heights, g(m) was significantly (19%) lower for leaves on tall trees compared with leaves on short trees. Overall, V(cmax) was 60% higher when expressed on the basis of CO(2) partial pressure at the chloroplasts, C(c), compared with V(cmax) on the basis of intercellular CO(2) partial pressure, C(i), but this varied with leaf age and tree size. To interpret the relative stomatal and mesophyll limitations to photosynthesis, we used a model of carbon isotopic composition for whole leaves incorporating g(m) effects to generate a surface of 'operating values' of A over the growing season for all leaf classes. Our analysis showed that A was slightly higher for leaves on short compared with tall trees, but lower g(m) apparently reduced actual A substantially compared with A(satQ). Our findings showed that lower rates of photosynthesis in Year 1 leaves compared with Year 0 leaves were attributable more to increased biochemical limitation to photosynthesis in Year 1 leaves than differences in g(m). However, lower A in leaves on tall trees compared with those on short trees could be attributed in part to lower g(m) and higher stomatal, L(s), and mesophyll, L(m), limitations to photosynthesis, consistent with steeper hydraulic gradients in tall trees.
[Pubmed: 21515907]
| | 25. |
2011 Nov 16 |
Distinct Roles of MicroRNA-1 and -499 in Ventricular Specification and Functional Maturation of Human Embryonic Stem Cell-Derived Cardiomyocytes
Fu, Rushing, Lieu, Chan, Kong, Geng, Wilson, Chiamvimonvat, Boheler, Wu, Keller, Hajjar, Li
PLoS One 2011 Nov 16;6(11). published online before print
Abstract
MicroRNAs (miRs) negatively regulate transcription and are important determinants of normal heart development and heart failure pathogenesis. Despite the significant knowledge gained in mouse studies, their functional roles in human (h) heart remain elusive.
[Pubmed: 22110643]
| | 26. |
2011 Nov 16 |
Atlas-Free Surface Reconstruction of the Cortical Grey-White Interface in Infants
Leroy, Mangin, Rousseau, Glasel, Hertz-Pannier, Dubois, Dehaene-Lambertz
PLoS One 2011 Nov 16;6(11). published online before print
Abstract
The segmentation of the cortical interface between grey and white matter in magnetic resonance images (MRI) is highly challenging during the first post-natal year. First, the heterogeneous brain maturation creates important intensity fluctuations across regions. Second, the cortical ribbon is highly folded creating complex shapes. Finally, the low tissue contrast and partial volume effects hamper cortex edge detection in parts of the brain.
[Pubmed: 22110604]
| | 27. |
2011 Nov 17 |
Demographic history, genetic structure and gene flow in a steppe-associated raptor species
Garcia, Alda, Terraube, Mougeot, Sternalski, Bretagnolle, Arroyo
BMC Evol Biol 2011 Nov 17;11:333. published online before print
Abstract
Environmental preferences and past climatic changes may determine the length of time during which a species range has contracted or expanded from refugia, thereby influencing levels of genetic diversification. Connectivity among populations of steppe-associated taxa might have been maximal during the long glacial periods, and interrupted only during the shorter interglacial phases, potentially resulting in low levels of genetic differentiation among populations. We investigated this hypothesis by exploring patterns of genetic diversity, past demography and gene flow in a raptor species characteristic of steppes, the Montagu's harrier (Circus pygargus), using mitochondrial DNA data from 13 breeding populations and two wintering populations.
[Pubmed: 22093489]
| | 28. |
2011 Nov 23 |
Bird Diversity, Birdwatching Tourism and Conservation in Peru: A Geographic Analysis
Puhakka, Salo, Sääksjärvi
PLoS One 2011 Nov 23;6(11). published online before print
Abstract
In the face of the continuing global biodiversity loss, it is important not only to assess the need for conservation, through e.g. gap analyses, but also to seek practical solutions for protecting biodiversity. Environmentally and socially sustainable tourism can be one such solution. We present a method to spatially link data on conservation needs and tourism-based economic opportunities, using bird-related tourism in Peru as an example. Our analysis highlighted areas in Peru where potential for such projects could be particularly high. Several areas within the central and northern Andean regions, as well as within the lowland Amazonian regions of Madre de Dios and Loreto emerge as promising for this type of activity. Mechanisms to implement conservation in these areas include e.g. conservation and ecotourism concessions, private conservation areas, and conservation easements. Some of these mechanisms also offer opportunities for local communities seeking to secure their traditional land ownership and use rights. (Spanish language abstract, Abstract S1).
[Pubmed: 22132078]
| | 29. |
2011 Nov 1 |
The genus
Anthia Weber in the Republic of South Africa, Identification, distribution, biogeography, and behavior (Coleoptera, Carabidae)
Mawdsley, Erwin, Sithole, Mawdsley, Mawdsley
Zookeys 2011 Nov 1;(143):47-81. published online before print
Abstract
A key is presented for the identification of the four species of Anthia Weber (Coleoptera: Carabidae) recorded from the Republic of South Africa: Anthia cinctipennis Lequien, Anthia circumscripta Klug, Anthia maxillosa (Fabricius), and Anthia thoracica (Thunberg). For each of these species, illustrations are provided of adult beetles of both sexes as well as illustrations of male reproductive structures, morphological redescriptions, discussions of morphological variation, annual activity histograms, and maps of occurrence localities in the Republic of South Africa. Maps of occurrence localities for these species are compared against ecoregional and vegetation maps of southern Africa; each species of Anthia shows a different pattern of occupancy across the suite of ecoregions and vegetation types in the Republic of South Africa. Information about predatory and foraging behaviors, Müllerian mimicry, and small-scale vegetation community associations is presented for Anthia thoracica based on field and laboratory studies in Kruger National Park, South Africa.
[Pubmed: 22144866]
| | 30. |
2011 Dec 13 |
Migrating deformation in the Central Andes from enhanced orographic rainfall.
Norton K, Schlunegger F
Nat Commun. 2011;2:584. Epub 2011 Dec 13.
Abstract
Active shortening in the Central Andes shifted from the western to the eastern margin between 10-7 Ma. Here we propose that this shift was primarily controlled by changes in erosion patterns. The uplift of the Andes blocked easterly winds, resulting in enhanced orographic rainfall on the eastern margin and reduced rainfall on the western margin. Lower erosion rates, associated with the arid conditions, caused the western margin to steepen inhibiting internal deformation and the migration of deformation to the eastern margin where it is active today. River channel profiles on the western margin are indicative of long-term transience from an older tectonic event whereas those on the eastern margin reflect ongoing coupled climatic-tectonic feedback. Both critical wedge theory and local-scale fault friction calculations support this interpretation. This work emphasizes the role that orographic rainfall and erosion can have on the orogen-scale development of mountain belts.
[Pubmed: 22158439]
| | 31. |
2011 Dec 7 |
No evidence of inbreeding avoidance despite demonstrated survival costs in a polygynous rodent.
Olson LE, Blumstein DT, Pollinger JR, Wayne RK
Mol. Ecol. 2011 Dec 7; [Epub ahead of print]
Abstract
Individuals are generally predicted to avoid inbreeding because of detrimental fitness effects. However, several recent studies have shown that limited inbreeding is tolerated by some vertebrate species. Here, we examine the costs and benefits of inbreeding in a largely polygynous rodent, the yellow-bellied marmot (Marmota flaviventris). We use a pedigree constructed from 8 years of genetic data to determine the relatedness of all marmots in our study population and examine offspring survival, annual male reproductive success, relatedness between breeding pairs and the effects of group composition on likelihood of male reproduction to assess inbreeding in this species. We found decreased survival in inbred offspring, but equal net reproductive success among males that inbred and those that avoided it. Relatedness between breeding pairs was greater than that expected by chance, indicating that marmots do not appear to avoid breeding with relatives. Further, male marmots do not avoid inbreeding: males mate with equal frequency in groups composed of both related and unrelated females and in groups composed of only female relatives. Our results demonstrate that inbreeding can be tolerated in a polygynous species if the reproductive costs of inbreeding are low and individuals that mate indiscriminately do not suffer decreased reproductive success.
[Pubmed: 22145620]
| | 32. |
2011 Nov 3 |
Fatal S. aureus Hemorrhagic Pneumonia: Genetic Analysis of a Unique Clinical Isolate Producing both PVL and TSST-1
Li, Stevens, Hamilton, Parimon, Ma, Kearns, Ellis, Bryant
PLoS One 2011 Nov 3;6(11). published online before print
Abstract
In 2008, an unusual strain of methicillin-sensitive Staphylococcus aureus (MSSA68111), producing both Panton-Valentine leukocidin (PVL) and toxic shock syndrome toxin-1 (TSST-1), was isolated from a fatal case of necrotizing pneumonia. Because PVL/TSST-1 co-production in S. aureus is rare, we characterized the molecular organization of these toxin genes in strain 68111. MSSA68111 carries the PVL genes within a novel temperate prophage we call ФPVLv68111 that is most similar, though not identical, to phage ФPVL – a phage type that is relatively rare worldwide. The TSST-1 gene (tst) in MSSA68111 is carried on a unique staphylococcal pathogenicity island (SaPI) we call SaPI68111. Features of SaPI68111 suggest it likely arose through multiple major recombination events with other known SaPIs. Both ФPVLv68111 and SaPI68111 are fully mobilizable and therefore transmissible to other strains. Taken together, these findings suggest that hypervirulent S. aureus have the potential to emerge worldwide.
[Pubmed: 22110621]
| | 33. |
2011 Nov |
Temporal blastemal cell gene expression analysis in the kidney reveals new Wnt and related signaling pathway genes to be essential for Wilms' tumor onset
Maschietto, Trapé, Piccoli, Ricca, Dias, Coudry, Galante, Torres, Fahhan, Lourenço, Grundy, de Camargo, de Souza, Neves, Soares, Brentani, Carraro
Cell Death Dis 2011 Nov;2(11):e224-.
Abstract
Wilms' tumors (WTs) originate from metanephric blastema cells that are unable to complete differentiation, resulting in triphasic tumors composed of epithelial, stromal and blastemal cells, with the latter harboring molecular characteristics similar to those of the earliest kidney development stages. Precise regulation of Wnt and related signaling pathways has been shown to be crucial for correct kidney differentiation. In this study, the gene expression profile of Wnt and related pathways was assessed in laser-microdissected blastemal cells in WTs and differentiated kidneys, in human and in four temporal kidney differentiation stages (i.e. E15.5, E17.5, P1.5 and P7.5) in mice, using an orthologous cDNA microarray platform. A signaling pathway-based gene signature was shared between cells of WT and of earliest kidney differentiation stages, revealing genes involved in the interruption of blastemal cell differentiation in WT. Reverse transcription-quantitative PCR showed high robustness of the microarray data demonstrating 75 and 56% agreement in the initial and independent sample sets, respectively. The protein expression of CRABP2, IGF2, GRK7, TESK1, HDGF, WNT5B, FZD2 and TIMP3 was characterized in WTs and in a panel of human fetal kidneys displaying remarkable aspects of differentiation, which was recapitulated in the tumor. Taken together, this study reveals new genes candidate for triggering WT onset and for therapeutic treatment targets.
[Pubmed: 22048167]
| | 34. |
2011 Nov 1 |
Viruses Infecting Reptiles
Marschang
Viruses 2011 Nov 1;3(11):2087-2126. published online before print
Abstract
A large number of viruses have been described in many different reptiles. These viruses include arboviruses that primarily infect mammals or birds as well as viruses that are specific for reptiles. Interest in arboviruses infecting reptiles has mainly focused on the role reptiles may play in the epidemiology of these viruses, especially over winter. Interest in reptile specific viruses has concentrated on both their importance for reptile medicine as well as virus taxonomy and evolution. The impact of many viral infections on reptile health is not known. Koch’s postulates have only been fulfilled for a limited number of reptilian viruses. As diagnostic testing becomes more sensitive, multiple infections with various viruses and other infectious agents are also being detected. In most cases the interactions between these different agents are not known. This review provides an update on viruses described in reptiles, the animal species in which they have been detected, and what is known about their taxonomic positions.
[Pubmed: 22163336]
| | 35. |
2011 Nov 22 |
Ecopathology of Ranaviruses Infecting Amphibians
Miller, Gray, Storfer
Viruses 2011 Nov 22;3(11):2351-2373. published online before print
Abstract
Ranaviruses are capable of infecting amphibians from at least 14 families and over 70 individual species. Ranaviruses infect multiple cell types, often culminating in organ necrosis and massive hemorrhaging. Subclinical infections have been documented, although their role in ranavirus persistence and emergence remains unclear. Water is an effective transmission medium for ranaviruses, and survival outside the host may be for significant duration. In aquatic communities, amphibians, reptiles and fish may serve as reservoirs. Controlled studies have shown that susceptibility to ranavirus infection and disease varies among amphibian species and developmental stages, and likely is impacted by host-pathogen coevolution, as well as, exogenous environmental factors. Field studies have demonstrated that the likelihood of epizootics is increased in areas of cattle grazing, where aquatic vegetation is sparse and water quality is poor. Translocation of infected amphibians through commercial trade (e.g., food, fish bait, pet industry) contributes to the spread of ranaviruses. Such introductions may be of particular concern, as several studies report that ranaviruses isolated from ranaculture, aquaculture, and bait facilities have greater virulence (i.e., ability to cause disease) than wild-type isolates. Future investigations should focus on the genetic basis for pathogen virulence and host susceptibility, ecological and anthropogenic mechanisms contributing to emergence, and vaccine development for use in captive populations and species reintroduction programs.
[Pubmed: 22163349]
| | 36. |
2011 Dec 2 |
Mutation Screening of Multiple Genes in Spanish Patients with Autosomal Recessive Retinitis Pigmentosa by Targeted Resequencing
González-del Pozo, Borrego, Barragán, Pieras, Santoyo, Matamala, Naranjo, Dopazo, Antiñolo
PLoS One 2011 Dec 2;6(12). published online before print
Abstract
Retinitis Pigmentosa (RP) is a heterogeneous group of inherited retinal dystrophies characterised ultimately by the loss of photoreceptor cells. RP is the leading cause of visual loss in individuals younger than 60 years, with a prevalence of about 1 in 4000. The molecular genetic diagnosis of autosomal recessive RP (arRP) is challenging due to the large genetic and clinical heterogeneity. Traditional methods for sequencing arRP genes are often laborious and not easily available and a screening technique that enables the rapid detection of the genetic cause would be very helpful in the clinical practice. The goal of this study was to develop and apply microarray-based resequencing technology capable of detecting both known and novel mutations on a single high-throughput platform. Hence, the coding regions and exon/intron boundaries of 16 arRP genes were resequenced using microarrays in 102 Spanish patients with clinical diagnosis of arRP. All the detected variations were confirmed by direct sequencing and potential pathogenicity was assessed by functional predictions and frequency in controls. For validation purposes 4 positive controls for variants consisting of previously identified changes were hybridized on the array. As a result of the screening, we detected 44 variants, of which 15 are very likely pathogenic detected in 14 arRP families (14%). Finally, the design of this array can easily be transformed in an equivalent diagnostic system based on targeted enrichment followed by next generation sequencing.
[Pubmed: 22164218]
| | 37. |
2011 Dec 2 |
The GATA1-HS2 Enhancer Allows Persistent and Position-Independent Expression of a β-globin Transgene
Miccio, Poletti, Tiboni, Rossi, Antonelli, Mavilio, Ferrari
PLoS One 2011 Dec 2;6(12). published online before print
Abstract
Gene therapy of genetic diseases requires persistent and position-independent expression of a therapeutic transgene. Transcriptional enhancers binding chromatin-remodeling and modifying complexes may play a role in shielding transgenes from repressive chromatin effects. We tested the activity of the HS2 enhancer of the GATA1 gene in protecting the expression of a β-globin minigene delivered by a lentiviral vector in hematopoietic stem/progenitor cells. Gene expression from proviruses carrying GATA1-HS2 in both LTRs was persistent and resistant to silencing at most integration sites in the in vivo progeny of human hematopoietic progenitors and murine long-term repopulating stem cells. The GATA1-HS2-modified vector allowed correction of murine β-thalassemia at low copy number without inducing clonal selection of erythroblastic progenitors. Chromatin immunoprecipitation studies showed that GATA1 and the CBP acetyltransferase bind to GATA1-HS2, significantly increasing CBP-specific histone acetylations at the LTRs and β-globin promoter. Recruitment of CBP by the LTRs thus establishes an open chromatin domain encompassing the entire provirus, and increases the therapeutic efficacy of β-globin gene transfer by reducing expression variegation and epigenetic silencing.
[Pubmed: 22164220]
| | 38. |
2011 Dec 12 |
Patterns of spatio-temporal distribution of winter chronic photoinhibition in leaves of three evergreen Mediterranean species with contrasting acclimation responses.
Silva-Cancino MC, Esteban R, Artetxe U, García Plazaola JI
Physiol Plant. 2011 Dec 12; [Epub ahead of print]
Abstract
High irradiance and relatively low temperature, which characterize Mediterranean winters, cause chilling stress in plants. Down-regulation of photosynthetic efficiency is a mechanism that allows plants to survive these conditions. The present study aims to address whether this process shows a regular spatial pattern across leaf surface or not. Three species (Buxus sempervirens, Cistus albidus and Arctostaphylos uva-ursi) with contrasting responses to winter stress were studied. During seven days, macro and micro Fv/Fm spatial patterns were monitored by the use of chlorophyll fluorescence imaging techniques. In the field, the strongest photoinhibition was found in Buxus sempervirens, while there was almost no chronic photoinhibition in Cistus albidus. In leaves of the first species, Fv/Fm decreased from base to tip while in Cistus albidus it was uniform over the leaf lamina. An intermediate behavior is shown by Arctostaphylos uva-ursi leaves. Spatial heterogeneity distribution of Fv/Fm was found inside the leaves, resulting in greater Fv/Fm values in the inner layers than in the outer ones. Neither Xanthophyll-linked down-regulation of Fv/Fm nor protein remobilization were the reasons for such spatial patterns since pigment composition and nitrogen content did not reveal tip-base differences. During recovery from winter, photoinhibition changes occurred in Fv/Fm, pigments, and chloroplast-ultrastructure. This work demonstrates for the first time that irrespective of physiological mechanisms responsible for development of winter photoinhibition, there is an acclimation response with strong spatio-temporal variability at leaf level in some species. This observation should be taken into account when modeling or scaling up photosynthetic responses.
[Pubmed: 22150512]
| | 39. |
2011 Dec 9 |
Inhibitory effects of kaempferol-3-O-sophoroside on HMGB1-mediated proinflammatory responses.
Kim TH, Ku SK, Bae JS
Food Chem Toxicol. 2011 Dec 9; [Epub ahead of print]
Abstract
High mobility group box 1 (HMGB1) protein is secreted by activated cells of the innate immune system and/or released by injured tissues and necrotic cells; HMGB1 up-regulates proinflammatory cytokines in several inflammatory diseases. Kaempferol-3-O-sophoroside (KP) was isolated from the leaves of cultivated mountain ginseng. KP has antitumor, antioxidative, antiallergic and antidiabetic activities, but the effects of KP on HMGB1-mediated proinflammatory responses have not been studied. In this study, we monitored the effect of KP on the lipopolysaccharide (LPS)-mediated release of HMGB1 and the HMGB1-mediated modulation of proinflammatory responses in human endothelial cells. We found that KP potently inhibited the release of HMGB1 by LPS and inhibited LPS- or HMGB1-mediated barrier permeability and expression of cell adhesion molecules. Further studies revealed that KP inhibited cell surface receptor of HMGB1, toll-like receptor (TLR) 2/4, but not the receptor for advanced glycation end products (RAGE). Collectively, these results suggest that KP possesses anti-inflammatory responses against HMGB1-mediated proinflammatory responses, thereby endorsing its usefulness as a therapy for vascular inflammatory diseases.
[Pubmed: 22178603]
| | 40. |
2011 Nov 28 |
The comparative effects of environmental enrichment with exercise and serotonin transporter blockade on serotonergic neurons in the dorsal raphe nucleus.
Macgillivray L, Reynolds K, Rosebush P, Mazurek M
Synapse. 2011 Nov 28; [Epub ahead of print]
Abstract
We have previously reported that inhibition of the serotonin transporter (SERT) by selective serotonin reuptake inhibitor (SSRI) fluoxetine significantly reduces the number of tryptophan hydroxylase (TPH)-positive cells in the dorsal raphe nucleus. We have been interested in exploring whether this SSRI-induced change in TPH might be modified by housing in an enriched environment. Like SSRI antidepressants, environmental enrichment (EE) and physical exercise have been found to have efficacy in the prevention and alleviation of depression. We postulated that EE with exercise and SERT inhibition would similarly affect TPH regulation and that EE with exercise might modify the effect of fluoxetine on TPH. Three week old male Sprague-Dawley rats were housed in either a standard cage (SE) or an enriched environment (EE). SE animals were singly housed with no access to enrichment objects. EE animals were group housed and were provided with various enrichment objects (e.g. running wheel) that were changed and rearranged regularly. Nine weeks after the experiment began, the rats were randomly assigned to one of four treatment groups: (1) SE control; (2) SE fluoxetine; (3) EE control; or (4) EE fluoxetine. Fluoxetine (5 mg/kg/day) was placed in the drinking water. Sections of dorsal raphe (DRN) were processed for TPH immunohistochemistry. The number of TPH-positive cells was determined by blinded, manual counting. Results were analyzed by analysis of variance (ANOVA) followed by post-hoc Tukey tests. Significance was set at p<0.05. For animals housed in a standard environment, fluoxetine induced a significant 27% reduction in the number of TPH-immunoreactive cells in the DRN. A similar reduction in TPH immunoreactivity was observed in animals that were housed in an enriched environment but not exposed to fluoxetine (39%). The number of TPH-positive cells in the DRN for animals housed in an enriched environment and exposed to fluoxetine was not significantly different than animals housed in an enriched environment and not exposed to fluoxetine. The reduction of TPH immunoreactivity in the DRN by EE with exercise suggests that a modified housing environment and voluntary exercise affects regulation of TPH, either via a mechanism similar to that of SERT inhibitors or through an independent pathway entirely. This downregulation of serotonin biosynthesis by fluoxetine and EE with exercise may ultimately play a role in the therapeutic action of both interventions. Synapse, 2011. © 2011 Wiley-Liss, Inc.
[Pubmed: 22121041]
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