ObjectivesPneumoconiosis remains a major global occupational health hazard and illness. Accurate data on the incidence of pneumoconiosis are critical for health resource planning and development of health policy.MethodsWe collected data for the period between 1990 and 2017 on the annual incident cases and the age-standardised incidence rates (ASIR) of pneumoconiosis aetiology from the Global Burden of Disease Study 2017. We calculated the average annual percentage changes of ASIR by sex, region and aetiology in order to determine the trends of pneumoconiosis.ResultsGlobally, the number of pneumoconiosis cases increased by a measure of 66.0%, from 36 186 in 1990 to 60 055 in 2017. The overall ASIR decreased by an average of 0.6% per year in the same period. The number of pneumoconiosis cases increased across the five sociodemographic index regions, and there was a decrease in the ASIR from 1990 to 2017. The ASIR of silicosis, coal workers’ pneumoconiosis and other pneumoconiosis decreased. In contrast, measures of the ASIR of asbestosis displayed an increasing trend. Patterns of the incidence of pneumoconiosis caused by different aetiologies were found to have been heterogeneous for analyses across regions and among countries.ConclusionIncidence patterns of pneumoconiosis which were caused by different aetiologies varied considerably across regions and countries of the world. The patterns of incidence and temporal trends should facilitate the establishment of more effective and increasingly targeted methods for prevention of pneumoconiosis and reduce associated disease burden.

As the most abundant biological entities on the planet, viruses significantly influence the overall functioning of marine ecosystems. The abundance, distribution, and biodiversity of viral communities in the upper ocean have been relatively well studied, but our understanding of viruses in the hadal biosphere remains poor. Here, we established the oceanic trench viral genome dataset (OTVGD) by analysing 19 microbial metagenomes derived from seawater and sediment samples of the Mariana, Yap, and Kermadec Trenches. The trench viral communities harbored remarkably high novelty, and they were predicted to infect ecologically important microbial clades, including Thaumarchaeota and Oleibacter. Significant inter-trench and intra-trench exchange of viral communities was proposed. Moreover, viral communities in different habitats (seawater/sediment and depth-stratified ocean zones) exhibited distinct niche-dependent distribution patterns and genomic properties. Notably, microbes and viruses in the hadopelagic seawater seemed to preferably adopt lysogenic lifestyles compared to those in the upper ocean. Furthermore, niche-specific auxiliary metabolic genes were identified in the hadal viral genomes, and a novel viral D-amino acid oxidase was functionally and phylogenetically characterized, suggesting the contribution of these genes in the utilization of refractory organic matter. Together, these findings highlight the genomic novelty, dynamic movement, and environment-driven diversification of viral communities in oceanic trenches, and suggest that viruses may influence the hadal ecosystem by reprogramming the metabolism of their hosts and modulating the community of keystone microbes.

SummaryPhylogenetic diversity of Synechococcus with different pigmentation in subtropical estuarine and coastal waters of Hong Kong was revealed by the phylogeny of cpcBA and cpeBA operons encoding for phycocyanin (PC) and phycoerythrin (PE). Synechococcus containing only PC (PC-rich Synechococcus) dominated at the estuarine station in summer, whereas PE-rich marine Synechococcus containing both PC and PE (PE-rich Synechococcus) dominated in the coastal waters. Our PC sequences are closely related to freshwater strains but differed from Baltic Sea strains, implying that they were from river discharge. Among PE-rich Synechococcus, clones grouping with strains containing only phycoerythrobilin (PEBonly) were abundant in July, while clones grouping with strains possessing a low content of phycourobilin (PUB) in addition to PEB (low PUB/PEB) were more abundant in January at both stations. Clones of high PUB/PEB types were only presented at the coastal station, but were not detected at the estuarine station. The much higher diversity of both PC-rich and PE-rich Synechococcus, as compared with the Baltic Sea, and the occurrence of the high PUB/PEB strains indicate the high dynamic nature of this subtropical estuarine-coastal environment with strong mixing of water masses ranging from Pearl River plume to oceanic South China Sea water. Our results of phylogenetic study agreed well with flow cytometric counts, which revealed the coexistence of PC-rich and PE-rich Synechococcus in the subtropical coastal waters and the dominance of the former type in the estuarine waters during summer high freshwater discharge. These results indicate that picocyanobacteria, particularly PC-rich Synechococcus, which has long been overlooked, are an important part of the primary production, and they could play an important role in the microbial food web in estuarine ecosystems.

2 mcyD KS copies ml ؊1 , while the microcystin concentration was barely detectable. The Q-PCR method allowed the detection of microcystin-producing cyanobacteria when toxins and toxigenic cyanobacterial abundance were still below the limit of detection by high-pressure liquid chromatography (HPLC) and microscopy. Toxin gene copy numbers grew exponentially at a steady rate over a period of 7 weeks. Onshore winds selected for cells with a higher cell quota of microcystin. This technique could be an effective approach for the routine monitoring of the most at-risk water bodies.

We examined the phylogenetic diversity and abundance of diazotrophs along a transect from the Pearl River plume to oceanic waters in the northern South China Sea by constructing a clone library and using the quantitative polymerase chain reaction (qPCR). All the diazotrophic phylogenetic groups recovered, including heterotrophic proteobacteria, phototrophic cyanobacteria and Cluster III diazotrophs, and showed distinct spatio-temporal variation along the transect. At the oceanic sampling stations, gammaproteobacteria formed the dominant diazotrophic group, with cyanobacterial diazotrophs accounting for only a relatively small proportion; at the station influenced by the Pearl River plume all the diazotrophs were non-cyanobacterial, making this station distinct from the other stations. Multidimensional analysis demonstrated that salinity was the key environmental factor determining the spatio-temporal variations of diazotrophic communities along the transect. Trichodesmium spp. were the most abundant among the cyanobacterial diazotrophs and were potentially the most important nitrogen fixers at all the oceanic stations. The absence of cyanobacterial diazotrophs in winter, and at the station influenced by the plume, could be due to the relatively high nutrient conditions in these waters. KEY WORDS: Diazotrophs · nifH gene · Phylogenetic diversity · qPCR · South China Sea Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 65: 15-27, 2011 16 copy numbers of nifH genes in genomic DNA, thus enabling the study of the environmental diazotrophic community (Zehr & McReynolds 1989).A wide range of diazotrophs have been discovered in aquatic ecosystems, all of which occur in the domains Bacteria and Archaea (Chien & Zinder 1994, Zehr et al. 2003. Proteobacteria and Cyanobacteria are the 2 main groups of diazotrophic bacteria inhabiting the upper marine ecosystems. Among them, Cyanobacteria are well-studied and the filamentous cyanobacterium Trichodesmium spp. is reported to be abundant in oligotrophic tropical and subtropical oceans (Carpenter & Romans 1991, Capone et al. 1997. Oceanic symbiotic Cyanobacteria, such as Richelia sp., occur as endosymbionts in some genera of diatoms, such as Rhizosolenia, Hemiaulus and Chaetoceros, and are also important nitrogen fixers (Carpenter et al. 1999, Foster & Zehr 2006. More recently, unicellular diazotrophic cyanobacteria, named group A (UCYN-A), group B (UCYN-B) and group C (UCYN-C), have been discovered on the basis of molecular techniques (Zehr et al. 2001, Langlois et al. 2005, Foster et al. 2007, and their contribution to total nitrogen fixation was estimated to be equal to, or even greater than, that of Trichodesmium spp. (Falcón et al. 2004, Goebel et al. 2007.Although most cyanobacterial diazotrophic groups can be detected simultaneously in the marine environment (Church et al. 2005a, Foster et al. 2007, Fong et al. 2008, different diazotrophic groups have shown different patterns of distribution in the ocean (Rieman...

Community composition of Bacteria in the surface and deep water layers were examined at three oceanic sites in the Pacific Ocean separated by great distance, i.e., the South China Sea (SCS) in the western tropical Pacific, the Costa Rica Dome (CRD) in the eastern tropical Pacific and the western subarctic North Pacific (SNP), using high throughput DNA pyrosequencing of the 16S rRNA gene. Bioinformatic analysis rendered a total of 143600 high quality sequences with an average 11967 sequences per sample and mean read length of 449 bp. Phylogenetic analysis showed that Proteobacteria dominated in all shallow and deep waters, with Alphaproteobacteria and Gammaproteobacteria the two most abundant components, and SAR11 the most abundant group at family level in all regions. Cyanobacteria occurred mainly in the surface euphotic layer, and the majority of them in the tropical waters belonged to the GpIIa family including Prochlorococcus and Synechococcus, whilst those associated with Cryptophytes and diatoms were common in the subarctic waters. In general, species richness (Chao1) and diversity (Shannon index H′) were higher for the bacterial communities in the intermediate water layers than for those in surface and deep waters. Both NMDS plot and UPGMA clustering demonstrated that bacterial community composition in the deep waters (500 m ∼2000 m) of the three oceanic regions shared a high similarity and were distinct from those in the upper waters (5 m ∼100 m). Our study indicates that bacterial community composition in the DOC-poor deep water in both tropical and subarctic regions were rather stable, contrasting to those in the surface water layers, which could be strongly affected by the fluctuations of environmental factors.

The composition and metabolic functions of prokaryotic communities in the western subarctic Pacific (WSP), where strong mixing of waters from the Sea of Okhotsk and the East Kamchatka Current result in transfer to the Oyashio Current, were investigated using a shotgun metagenome sequencing approach. Functional metabolic genes related to nutrient cycling of nitrogen, sulfur, carbohydrates, iron and amino acids were differently distributed between the surface and deep waters of the WSP. Genes related to nitrogen metabolism were mainly found in deep waters, where Thaumarchaeaota, Sphingomonadales, and Pseudomonadales were closely associated and performing important roles in ammonia oxidation, assimilatory nitrate reduction, and dissimilatory nitrate reduction processes, respectively. In addition, orders affiliated to Spingobacteria and Alphaproteobacteria were crucial for sulfate reduction and abundant at 3000 m, whereas orders affiliated to Gammaproteobacteria, which harbored the most sulfate reduction genes, were abundant at 1000 m. Additionally, when compared with the East Kamchatka Current, the prokaryotes in the Oyashio Current were likely to consume more energy for synthesizing cellular components. Also, genes encoding iron transport and siderophore biosynthesis proteins were in low abundance, indicating that the iron was not a limiting factor in the Oyashio current. In contrast, in the East Kamchatka Current, prokaryotes were more likely to directly utilize the amino acids and absorb iron from the environment. Overall, our data indicated that the transformation from the East Kamchatka Current to the Oyashio Current reshapes not only the composition of microbial community, but also the function of the metabolic processes. These results extended our knowledge of the microbial composition and potential metabolism in the WSP.

[1] The regulation of bacterial metabolic activity by viruses and dissolved organic carbon (DOC) was examined using natural microbial communities in three treatments (active viruses, inactive viruses, and virus free) at two contrasting coastal sites (pristine vs. eutrophic) with substantial differences in environmental conditions during the wet and dry seasons. Our results showed that net growth rates and production of bacterioplankton were reduced primarily by viruses via repressing metabolically active bacteria with high nucleic acid (HNA) content which had a high capacity for incorporating carbon, while bacterial respiration was primarily regulated by DOC lability. The quality of organic matter played a more important role in regulating bacterial growth efficiency (BGE) than the supply of organic matter in eutrophic coastal waters. The lack of HMW-DOC and high carbon demand in the virus-free treatment resulted in a significant increase in cell-specific bacterial respiration, which was responsible for the lowest bacterial growth efficiency among the three treatments. The presence of viruses did not necessarily lower bacterial growth efficiency since virus-induced mortality alleviated bacterial carbon demand and enhanced carbon cycling. Virus-induced mortality was greater in relatively pristine waters than eutrophic waters, likely since the high supply of substrates alleviated the pressure of viral infection, through extracellular proteases produced by bacteria, which might result in the hydrolytic destruction or modification of viral capsids. An important implication of our results was that the input of riverine DOC and nutrients improved bacterial metabolic activity by alleviating virus-induced mortality of bacteria in estuarine and coastal waters.