Mid-ocean exchange of container vessel ballast water. 1: seasonal factors affecting the transport of harmful diatoms and dinoflagellates

Our study of 34 ships (20 direct from Oakland, California, USA, and 14 more after open ocean exchange) is the first year-long seasonal study to assess the effectiveness of open ocean exchange of ballast waters. The highest number of harmful species occurred in April and February when water temperatures in Hong Kong (China) and Oakland were low. The periods with the greatest species richness of harmful species did not correspond to periods with the highest abundance of harmful species. The latter occurred in early September and mid-August, when Skeletonema costatum (14000 cells l-1) dominated the plankton in the ballast water from Oakland Harbor. From April 1996 to April 1997, ballast water samples were collected from 34 Orient Overseas Container Lines Ltd ships which took 16 d to travel from Oakland to Hong Kong. Of the 34 ships, 14 exchanged their Oakland Harbor ballast water for open ocean water (referred to here as reballasting). Open ocean was defined as waters with a depth >2000 m. Once reballasting was completed, the contents of ballast tank no. 1 were not discharged until the ship reached Hong Kong. Six harmful diatoms and 9 harmful dinoflagellate species were observed in the ballast water from Oakland Harbor. These included the diatom Chaetoceros concavicornis and the PSP (paralytic shellfish poisoning) toxin producing dinoflagellate Alexandrium catenella. Of the 15 harmful species found in the Oakland Harbor ballast water, 8 (53%) were also found in the ballast water of ships that had exchanged coastal for open ocean ballast water. The abundance of harmful species in open ocean ballast water was 87% lower than those in the ballast water from Oakland Harbor. The reason that mid-ocean exchange failed to eliminate all harmful diatoms and dinoflagellates was probably because the ballast tank was never completely emptied before it was reballasted with mid-ocean water.published_or_final_versio

Mid-ocean exchange of container vessel ballast water. 2: effects of vessel type in the transport of diatoms and dinoflagellates from Manzanillo, Mexico, to Hong Kong, China

Plankton samples were collected from 4 container ships which took on ballast water in Manzanillo, Mexico, and discharged it 21 d later in Hong Kong, China. As expected, the lack of light during transport in ballast tanks was inimical to the survival of many autotrophic (phytoplankton) species. After 21 d at sea, few of the dinoflagellate and diatom species taken on in Manzanillo Harbour were alive in the ballast water delivered to Hong Kong. In addition, 5 ships from Manzanillo which reballasted with open ocean water were sampled. To assess the effectiveness of mid-ocean exchange, the mean number of diatoms and dinoflagellates in the coastal ballast water (838 cells l-1) was compared with the number in the open ocean ballast water (436 cells l-1) delivered to Hong Kong. Open ocean exchange of ballast water (reballasting) was 48% effective in reducing diatom and dinoflagellate abundance. When we compared the Manzanillo study with our previous study of ships from Oakland, California, we concluded that the older container ships such as those coming from Manzanillo were not as effective in getting rid of diatom and dinoflagellate species as the newer container ships. This is probably because the reballasting design of the older ships is not as efficient in removing the water and sediments located near the bottom of the ballast tanks. This bottom water is associated with a large number of resting cysts and cells.published_or_final_versio

Identification and analysis of genomic islands in Burkholderia cenocepacia AU 1054 with emphasis on pathogenicity islands

published_or_final_versio

Hexaaquamagnesium bis{trans-[nitrilotriacetato(2-)-κ(3)O(1),N,O(2)]-μ-oxo-cis-dioxomolybdate(VI)} hexahydrate

Both the cation and anion in the title compound, [Mg(H2O)(6)][Mo2O5(C6H7NO6)(2)]. 6H(2)O, lie on centers of symmetry, and their metals are both six-coordinate in octahedral environments

Maintenance of age in human neurons generated by microRNA-based neuronal conversion of fibroblasts

Aging is a major risk factor in many forms of late-onset neurodegenerative disorders. The ability to recapitulate age-related characteristics of human neurons in culture will offer unprecedented opportunities to study the biological processes underlying neuronal aging. Here, we show that using a recently demonstrated microRNA-based cellular reprogramming approach, human fibroblasts from postnatal to near centenarian donors can be efficiently converted into neurons that maintain multiple age-associated signatures. Application of an epigenetic biomarker of aging (referred to as epigenetic clock) to DNA methylation data revealed that the epigenetic ages of fibroblasts were highly correlated with corresponding age estimates of reprogrammed neurons. Transcriptome and microRNA profiles reveal genes differentially expressed between young and old neurons. Further analyses of oxidative stress, DNA damage and telomere length exhibit the retention of age-associated cellular properties in converted neurons from corresponding fibroblasts. Our results collectively demonstrate the maintenance of age after neuronal conversion. DOI: http://dx.doi.org/10.7554/eLife.18648.00

Knowledge and risk behaviors related to HIV/AIDS, and their association with information resource among men who have sex with men in Heilongjiang province, China

<p>Abstract</p> <p>Backgroud</p> <p>In Heilongjiang province, the HIV prevalence in men who have sex with men (MSM) is generally lower than other part of China. However, the official perception for their risk of HIV/AIDS infection has been increasing in the province over the years. Moreover, little information on HIV/AIDS was provided to the communities so that we have disadvantage of controlling HIV/AIDS epidemic in the region. The purpose of this study is to investigate the prevalence of HIV among MSM in Heilongjiang province, to assess their knowledge levels and risk behaviors related to HIV/AIDS, and to explore their associations with information resources.</p> <p>Methods</p> <p>A cross-sectional study using a standardized questionnaire and blood test was administered in 2008 by local interviewers to a sample (1353) of MSM in four cities in Heilongjiang province.</p> <p>Results</p> <p>Among 1353 MSM, 2.3% were identified with HIV infection. About 48.7% of the subjects had multiple male sexual partners and only 37.3% of the subjects had consistent condom use (use every time) in the past 6 months. Most had a fair level of knowledge on HIV/AIDS, with the highest mean knowledge score among the MSM from Jiamusi, those with income 2000-3000 RMB/month, those searching sexual partners via internet and those performed HIV testing over 1 year ago). However, some myths regarding viral transmission (e.g., via mosquito bites or sharing kitchen utensils) also existed. Resources of information from which knowledge and risk behaviors related to HIV/AIDS was most available were television (58.6%) among MSM, followed by sexual partner (51.6%), publicity material (51.0%) and internet (48.7%). Significantly statistical differences of mean knowledge score were revealed in favor of book (<it>P </it>= 0.0002), medical staff (<it>P </it>= 0.0007), publicity material (<it>P </it>= 0.005) and sexual partner (<it>P </it>= 0.02). Press (<it>P </it>= 0.04) and book (<it>P </it>= 0.0003) were contributory to the most frequent condom use (condom use every time), while medical staff (<it>P </it>= 0.005) and publicity material (<it>P </it>= 0.04) is associated with moderate rate of condom use (condom use often).</p> <p>Conclusions</p> <p>Although the prevalence of HIV infection is low among MSM in Heilongjiang province, the situation that the risk behaviors were frequent in the population is alarming. The study suggests that some strategies like condom use and education intervention are practical approaches and need to be strengthened.</p

Identifying Ligand Binding Conformations of the β2-Adrenergic Receptor by Using Its Agonists as Computational Probes

Recently available G-protein coupled receptor (GPCR) structures and biophysical studies suggest that the difference between the effects of various agonists and antagonists cannot be explained by single structures alone, but rather that the conformational ensembles of the proteins need to be considered. Here we use an elastic network model-guided molecular dynamics simulation protocol to generate an ensemble of conformers of a prototypical GPCR, β2-adrenergic receptor (β2AR). The resulting conformers are clustered into groups based on the conformations of the ligand binding site, and distinct conformers from each group are assessed for their binding to known agonists of β2AR. We show that the select ligands bind preferentially to different predicted conformers of β2AR, and identify a role of β2AR extracellular region as an allosteric binding site for larger drugs such as salmeterol. Thus, drugs and ligands can be used as "computational probes" to systematically identify protein conformers with likely biological significance. © 2012 Isin et al

Modulation of Sn concentration in ZnO nanorod array: intensification on the conductivity and humidity sensing properties

Tin (Sn)-doped zinc oxide (ZnO) nanorod arrays (TZO) were synthesized onto aluminum-doped ZnO-coated glass substrate via a facile sonicated sol–gel immersion method for humidity sensor applications. These nanorod arrays were grown at different Sn concentrations ranging from 0.6 to 3 at.%. X-ray diffraction patterns showed that the deposited TZO arrays exhibited a wurtzite structure. The stress/strain condition of the ZnO film metamorphosed from tensile strain/compressive stress to compressive strain/tensile stress when the Sn concentrations increased. Results indicated that 1 at.% Sn doping of TZO, which has the lowest tensile stress of 0.14 GPa, generated the highest conductivity of 1.31 S cm− 1. In addition, 1 at.% Sn doping of TZO possessed superior sensitivity to a humidity of 3.36. These results revealed that the optimum performance of a humidity-sensing device can be obtained mainly by controlling the amount of extrinsic element in a ZnO film