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An ultra-high-pressure liquid chromatography/MS3 (UPLC-MS3) method has been developed and validated for the quantitative determination of four major TSNAs in mainstream cigarette smoke using MS3 scan mode on a hybrid triple quadrupole-linear ion trap mass spectrometer. The new method combining the UPLC with MS3 scan mode offers decreased sample analysis time and good selectivity. After mainstream cigarette smoke was collected on a Cambridge filter pad, the particulate matter was extracted with ammonium acetate solution and analyzed by UPLC-MS3 using isotopically labeled analogues as internal standards. Four TSNAs were completely separated on an Agilent XDB-C18 UPLC column using isocratic elution during a 6 min LC run time. Excellent linearity was obtained over the concentration range of 1.0-150.0 ng/mL for all TSNAs with values for correlation coefficient (r) between 0.9985-0.9994. Limits of detection (LOD) of each TSNA varied from 0.023 to 0.067 ng/mL, and lower limits of quantification (LLOQ) varied from 0.077 to 0.223 ng/mL, respctively. The recovery of each TSNA was from 89.2 to 106.8%. The method achieved excellent reproducibility with RSD 2.1-6.8% for intra-assay and 3.4-9.1% for inter-assay. This method can be used as an effective approach to significantly improve the detection capability for TSNAs in complex matrices.

The bighead carp Hypophthalmichthys nobilis is native to China but has been introduced to over 70 countries and is established in many large river systems. Genetic diversity and variation in introduced bighead carp have not previously been evaluated, and a systematic comparison among fish from different river systems was unavailable. In this study, 190 bighead carp specimens were sampled from five river systems in three countries (Yangtze, Pearl, and Amur rivers, China; Danube River, Hungary; Mississippi River basin, USA) and their mitochondrial 16S ribosomal RNA gene and D-loop region were sequenced (around 1,345 base pairs). Moderate genetic diversity was found in bighead carp, ranging from 0.0014 to 0.0043 for nucleotide diversity and from 0.6879 to 0.9333 for haplotype diversity. Haplotype analysis provided evidence that (1) multiple haplotype groups might be present among bighead carp, (2) bighead carp probably originated from the Yangtze River, and (3) bighead carp in the Mississippi River ...

Based upon morphological characters, Silver carp Hypophthalmichthys molitrix and bighead carp Hypophthalmichthys nobilis (or Aristichthys nobilis) have been classified into either the same genus or two distinct genera. Consequently, the taxonomic relationship of the two species at the generic level remains equivocal. This issue is addressed by sequencing complete mitochondrial genomes of H. molitrix and H. nobilis, comparing their mitogenome organization, structure and sequence similarity, and conducting a comprehensive phylogenetic analysis of cyprinid species. As with other cyprinid fishes, the mitogenomes of the two species were structurally conserved, containing 37 genes including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA (tRNAs) genes and a putative control region (D-loop). Sequence similarity between the two mitogenomes varied in different genes or regions, being highest in the tRNA genes (98.8%), lowest in the control region (89.4%) and intermediate in the protein-coding genes (94.2%). Analyses of the sequence comparison and phylogeny using concatenated protein sequences support the view that the two species belong to the genus Hypophthalmichthys. Further studies using nuclear markers and involving more closely related species, and the systematic combination of traditional biology and molecular biology are needed in order to confirm this conclusion.

Seventeen microsatellite DNA loci from the Australian short-finned eel (Anguilla australis Richardson) were isolated and their amplification characteristics were described. The polymerase chain reaction primers were tested on 40 eel individuals. The primers amplified loci with relatively high numbers of alleles, ranging from five to 14 with an average of nine per locus. Mean observed heterozygosity (H(O) ) and expected heterozygosity (H(E) ) were 0.6779 and 0.7374, respectively, indicating that these markers would be useful for population studies. No loci deviated significantly from Hardy-Weinberg equilibrium (P = 0.05) and no evidence was found for genotypic disequilibrium among loci at a 5% significance level.