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In this study, a next-generation sequencing strategy on 16 S ribosomal RNA (16 S rRNA) gene was employed to analyze 70 oral samples from 32 patients with throat cancer, nine patients with vocal cord polyp, and 29 healthy individuals (normal controls). Using this strategy, we demonstrated, for the first time, that the salivary microbiota of cancer patients were significantly different from those of patients with a polyp and healthy individuals. We observed that the beta diversity of the cancer group was divergent from both the normal and polyp groups, while alpha-diversity indices such as the Chao1 estimator ( P = 8.1e-05), Simpson ( P = 0.0045), and Shannon ( P = 0.0071) were significantly reduced in cancer patients compared with patients containing a polyp and normal healthy individuals. Linear discriminant analysis (LDA) and Kruskal-Wallis test analyses and real-time quantitative polymerase chain reaction (qPCR) verification test revealed that the genera Aggregatibacter, Pseudomonas, Bacteroides , and Ruminiclostridium were significantly enriched in the throat cancer group compared with the vocal cord polyp and normal control groups (score value >2). Finally, diagnostic models based on putatively important constituent bacteria were constructed with 87.5% accuracy [area under the curve (AUC) = 0.875, 95% confidence interval (CI): 0.695-1]. In summary, in this study we characterized, for the first time, the oral microbiota of throat cancer patients without smoking history. We speculate that these results will help in the pathogenic mechanism and early diagnosis of throat cancer.

Denitrification plays a critical role in nitrogen removal in estuarine and coastal ecosystems. In this study, the community composition, diversity, abundance, and distribution of cytochrome cd1-type nitrite reductase gene (nirS)-harboring denitrifiers in intertidal sediments of the Yangtze Estuary were analyzed using polymerase chain reaction (PCR)-based clone libraries and quantitative PCR techniques. Clone library analysis showed that the nirS-encoding bacterial biodiversity was significantly higher at the lower salinity sites than at the higher salinity sites. However, there was no significant seasonal difference in the nirS gene diversity between summer and winter. Phylogenetic analysis revealed that the nirS-harboring denitrifier communities at the study area had distinctive spatial heterogeneity along the estuary. At the lower salinity sites, the nirS-harboring bacterial community was co-dominated by clusters III and VII; while at the higher salinity sites, it was dominated by cluster I. Canonical correspondence analysis indicated that the community compositions of nirS-type denitrifiers were significantly correlated with salinity, ammonium, and nitrate. Quantitative PCR results showed that the nirS gene abundance was in the range of 1.01 × 10(6) to 9.00 × 10(7) copies per gram dry sediment, without significant seasonal variation. Among all the environmental factors, the nirS gene abundance was only significantly related to the change of salinity. These results can extend our current knowledge about the composition and dynamics of denitrification microbial community in the estuarine ecosystem.

Ammonia oxidation plays a pivotal role in the cycling and removal of nitrogen in aquatic sediments. Certain bacterial groups and a novel group of archaea, which is affiliated with the novel phylum Thaumarchaeota, can perform this initial nitrification step. We examined the diversity and abundance of ammonia-oxidizing β-Proteobacteria (β-AOB) and ammonia-oxidizing archaea (AOA) in the sediments of Chongming eastern tidal flat using the ammonia monooxygenase-α subunit (amoA) gene as functional markers. Clone library analysis showed that AOA had a higher diversity of amoA gene than β-AOB. The β-Proteobacterial amoA community composition correlated significantly with water soluble salts in the sediments, whereas the archaeal amoA community composition was correlated more with nitrate concentrations. Quantitative PCR (qPCR) results indicated that the abundance of β-AOB amoA gene (9.11 × 10(4)-6.47 × 10(5) copies g(-1) sediment) was always greater than that of AOA amoA gene (7.98 × 10(3)-3.51 × 10(5) copies g(-1) sediment) in all the samples analyzed in this study. The β-Proteobacterial amoA gene abundance was closely related to organic carbon, while no significant correlations were observed between archaeal amoA gene abundance and the environmental factors. Potential nitrification rates were significantly greater in summer than in winter and correlated strongly with the abundance of amoA genes. Additionally, a greater contribution of single amoA gene to potential nitrification occurred in summer (1.03-5.39 pmol N copy(-1) day(-1)) compared with winter (0.16-0.38 pmol N copy(-1) day(-1)), suggesting a higher activity of ammonia-oxidizing prokaryotes in warm seasons.

It is widely recognized that unregulated harvesting and hunting of biological resources can be harmful and endanger ecosystems. Therefore, various measures to prevent the biological resources from destruction and to protect the ecological environment have been taken. An effective resolution is to designate protection zones where harvesting and hunting are prohibited. Assuming that migration can occur between protected and unprotected areas, a fundamental question is, how large should a protection zone be so that the species in both the protection subregion and natural environment are able to survive. Devoted to answering the question, this paper aims at studying ecosystems that are subject to random noise represented by Brownian motion. Sufficient conditions for permanence and extinction are obtained, which are sharp and close to necessary conditions. Moreover, ergodicity, convergence of probability measures to that of the invariant measure under total variation norm, and rates of convergence are obtained. [ABSTRACT FROM AUTHOR]

Abstract: Populations of biological species are often subject to different types of environmental noises. These noises play crucial roles and have significant impact on the evolution and biodiversity. To understand the effects of different types of noises on the asymptotic properties of the populations, this paper reveals the influence of inherent net birth noise and the interaction noise among stochastically perturbed population systems. By considering systems with infinite delays, (1) this paper discovers that (a) the interaction noise may suppress the potential explosion and guarantee the existence of the global solution, which yields regularity of the stochastic system, and (b) the inherent net birth noise may lead to extinction of the populations; (2) this paper provides sufficient conditions that ensure the stochastic persistence, stochastic boundedness, and asymptotic polynomial growth of the population system; (3) this paper demonstrates that these asymptotic properties are completely determined by stochastic noises and are independent of other parameters. [Copyright &y& Elsevier]