Alona iheringula Sinev & Kotov, 2004 (Crustacea, Anomopoda, Chydoridae, Aloninae): life cycle and DNA barcode with implications for the taxonomy of the Aloninae subfamily.

Knowledge of reproductive rates and life cycle of the Cladocera species is essential for population dynamic studies, secondary production and food webs, as well as the management and preservation of aquatic ecosystems. The present study aimed to understand the life cycle and growth of Alona iheringula Kotov & Sinev, 2004 (Crustacea, Anomopoda, Chydoridae), a Neotropical species, as well as its DNA barcoding, providing new information on the Aloninae taxonomy. The specimens were collected in the dammed portion of the Cabo Verde River (21°26'05″ S and 46°10'57″ W), in the Furnas Reservoir, Minas Gerais State, Brazil. Forty neonates were observed individually two or three times a day under controlled temperature (25±1°C), photoperiod (12 h light/12 h dark) and feeding (Pseudokirchneriella subcapitata at a concentration of 105 cells.mL-1 and a mixed suspension of yeast and fish feed in equal proportion). Individual body growth was measured daily under optical microscope using a micrometric grid and 40× magnification. The species had a mean size of 413(±29) µm, a maximum size of 510 µm and reached maturity at 3.24(±0.69) days of age. Mean fecundity was 2 eggs per female per brood and the mean number of eggs produced per female during the entire life cycle was 47.6(±6.3) eggs per female. The embryonic development time was 1.79(±0.23) days and the maximum longevity was 54 days. The species had eight instars throughout its life cycle and four instars between neonate and primipara stage. The present study using molecular data (a 461 bp smaller COI fragment) demonstrated a deep divergence in the Aloninae subfamily.

Bacterial origin of a diverse family of UDP-glycosyltransferase genes in the Tetranychus urticae genome.

UDP-glycosyltransferases (UGTs) catalyze the conjugation of a variety of small lipophilic molecules with uridine diphosphate (UDP) sugars, altering them into more water-soluble metabolites. Thereby, UGTs play an important role in the detoxification of xenobiotics and in the regulation of endobiotics. Recently, the genome sequence was reported for the two-spotted spider mite, Tetranychus urticae, a polyphagous herbivore damaging a number of agricultural crops. Although various gene families implicated in xenobiotic metabolism have been documented in T. urticae, UGTs so far have not. We identified 80 UGT genes in the T. urticae genome, the largest number of UGT genes in a metazoan species reported so far. Phylogenetic analysis revealed that lineage-specific gene expansions increased the diversity of the T. urticae UGT repertoire. Genomic distribution, intron-exon structure and structural motifs in the T. urticae UGTs were also described. In addition, expression profiling after host-plant shifts and in acaricide resistant lines supported an important role for UGT genes in xenobiotic metabolism. Expanded searches of UGTs in other arachnid species (Subphylum Chelicerata), including a spider, a scorpion, two ticks and two predatory mites, unexpectedly revealed the complete absence of UGT genes. However, a centipede (Subphylum Myriapoda) and a water flea and a crayfish (Subphylum Crustacea) contain UGT genes in their genomes similar to insect UGTs, suggesting that the UGT gene family might have been lost early in the Chelicerata lineage and subsequently re-gained in the tetranychid mites. Sequence similarity of T. urticae UGTs and bacterial UGTs and their phylogenetic reconstruction suggest that spider mites acquired UGT genes from bacteria by horizontal gene transfer. Our findings show a unique evolutionary history of the T. urticae UGT gene family among other arthropods and provide important clues to its functions in relation to detoxification and thereby host adaptation.

Endocrine disruption and consequences of chronic exposure to ibuprofen in Japanese medaka (Oryzias latipes) and freshwater cladocerans Daphnia magna and Moina macrocopa.

Despite frequent detection of ibuprofen in aquatic environments, the hazards associated with long-term exposure to ibuprofen have seldom been investigated. Ibuprofen is suspected of influencing sex steroid hormones through steroidogenic pathways in both vertebrates and invertebrates. In this study, the effect of ibuprofen on sex hormone balance and the associated mechanisms was investigated in vitro by use of H295R cells. We also conducted chronic toxicity tests using freshwater fish, Oryzias latipes, and two freshwater cladocerans, Daphnia magna and Moina macrocopa, for up to 144 and 21d of exposure, respectively. Ibuprofen exposure increased 17beta-estradiol (E2) production and aromatase activity in H295R cells. Testosterone (T) production decreased in a dose-dependent manner. For D. magna, the 48 h immobilization EC50 was 51.4 mg/L and the 21 d reproduction NOEC was <1.23 mg/L; for M. macrocopa, the 48 h immobilization EC50 was 72.6 mg/L and the 7d reproduction NOEC was 25mg/L. For O. latipes, 120 d survival NOEC was 0.0001 mg/L. In addition, ibuprofen affected several endpoints related to reproduction of the fish, including induction of vitellogenin in male fish, fewer broods per pair, and more eggs per brood. Parental exposure to as low as 0.0001 mg/L ibuprofen delayed hatching of eggs even when they were transferred to and cultured in clean water. Delayed hatching is environmentally relevant because this may increase the risk of being predated. For O. latipes, the acute-to-chronic ratio of ibuprofen was estimated to be greater than 1000. Overall, relatively high acute-to-chronic ratio and observation of reproduction damage in medaka fish at environmentally relevant ranges of ibuprofen warrant the need for further studies to elucidate potential ecological consequences of ibuprofen contamination in the aquatic environment.