Marine genetic swamping: hybrids replace an obligately estuarine fish

Populations of obligately estuarine taxa are potentially small and isolated and may lack genetic variation and display regional differentiation as a result of drift and inbreeding. Hybridization with a wide‐ranging marine congener should introduce genetic variation and reduce the effects of inbreeding depression and genetic drift. However, high levels of hybridization can cause demographic and genetic swamping. In southeastern Australia hybridization occurs between obligately estuarine Black bream (Acanthopagrus butcheri) and migratory marine Yellowfin bream (Acanthopagrus australis). Here, we surveyed genetic variation at eight microsatellite loci and the mitochondrial control region of juvenile fish from five coastal lagoons (including temporal replication in two lagoons) (total n = 970) to determine the frequency and persistence of hybridization, and its likely consequence for the estuarine restricted A. butcheri. Of 688 juvenile fish genotyped 95% were either A. australis (347) or hybrids (309); only 5% (32) were A. butcheri. Most hybrids were later generation hybrids or A. butcheri backcrosses, which are likely multi‐generational residents within lagoons. Far greater proportions of hybrid juveniles were found within two lagoons that are generally closed to the ocean (>90% hybrid fish within generally closed lagoons vs. 12–27% in permanently or intermittently open lagoons). In both lagoons, this was consistent across multiple cohorts of fish [79–97% hybrid fish (n = 282)]. Hybridization and introgression represent a major threat to the persistence of A. butcheri and have yet to be investigated for large numbers of estuarine taxa.     

A molecular phylogeny for the pyraloid moths (Lepidoptera: Pyraloidea) and its implications for higher‐level classification

Pyraloidea, one of the largest superfamilies of Lepidoptera, comprise more than 15 684 described species worldwide, including important pests, biological control agents and experimental models. Understanding of pyraloid phylogeny, the basis for a predictive classification, is currently provisional. We present the most detailed molecular estimate of relationships to date across the subfamilies of Pyraloidea, and assess its concordance with previous morphology‐based hypotheses. We sequenced up to five nuclear genes, totalling 6633 bp, in each of 42 pyraloids spanning both families and 18 of the 21 subfamilies, plus up to 14 additional genes, for a total of 14 826 bp, in 21 of those pyraloids plus all 24 outgroups. Maximum likelihood analyses yield trees that, within Pyraloidea, differ little among datasets and character treatments and are strongly supported at all levels of divergence (83% of nodes with bootstrap ≥80%). Subfamily relationships within Pyralidae, all very strongly supported (>90% bootstrap), differ only slightly from a previous morphological analysis, and can be summarized as Galleriinae + Chrysauginae (Phycitinae (Pyralinae + Epipaschiinae)). The main remaining uncertainty involves Chrysauginae, of which the poorly studied Australian genera may constitute the basal elements of Galleriinae + Chrysauginae or even of Pyralidae. In Crambidae the molecular phylogeny is also strongly supported, but conflicts with most previous hypotheses. Among the newly proposed groupings are a ‘wet‐habitat clade’ comprising Acentropinae + Schoenobiinae + Midilinae, and a provisional ‘mustard oil clade’ containing Glaphyriinae, Evergestinae and Noordinae, in which the majority of described larvae feed on Brassicales. Within this clade a previous synonymy of Dichogaminae with the Glaphyriinae is supported. Evergestinae syn. n. and Noordinae syn. n. are here newly synonymized with Glaphyriinae, which appear to be paraphyletic with respect to both. Pyraustinae and Spilomelinae as sampled here are each monophyletic but form a sister group pair. Wurthiinae n. syn. , comprising the single genus Niphopyralis Hampson, which lives in ant nests, are closely related to, apparently subordinate within, and here newly synonymized with, Spilomelinae syn. n.     

Horizon annealing: a collection‐based approach to automated sequencing of the fossil record

Sheets, H.D., Mitchell, C.E., Izard, Z.T., Willis, J.M., Melchin, M.J. & Holmden, C. 2012: Horizon annealing: a collection‐based approach to automated sequencing of the fossil record. Lethaia, Vol. 45, pp. 532–547. A number of different approaches to quantitative biochronology have been proposed and used to construct high‐resolution time‐scales for a range of uses. We present a new approach, horizon annealing, which uses simulated annealing to optimize the sequencing of collection horizons. Temporal sequences of events produced by this method are compared with those produced by graphic correlation, CONOP and RASC for a series of previously studied exemplar data sets. Horizon annealing produces results similar to other methods, but it does have properties (the ordination of collections and the avoidance of some local minima) that make it useful for high‐resolution studies, particularly those based on capture‐mark‐recapture methods requiring detailed presence–absence data for individual collections and taxa. □ Chronostratigraphy, graphic correlation, graptolite, rate of evolution, CONOP9.     

Thermodynamics and Kinetics of MTBE Degradation: A Density Functional Theory Study

Computational studies using density functional theory can help define which of a variety of reactions may be involved in the degradation of the fuel oxygenate methyl tert-butyl ether (MTBE). It is shown that hydrolysis of MTBE in the vapor phase or in neutral aqueous media, as well as its unimolecular decomposition, are not significant degradation mechanisms. The acid catalyzed hydrolysis of MTBE is a more feasible degradation pathway and is shown to proceed via tert-butyl carbonium ion formation. Hydrogen abstraction is shown to be the dominant first step in the degradation of MTBE initiated by hydroxyl radicals.     

The role of nitric oxide in cancer

Nitric oxide (NO) is a pleiotropic regulator, critical to numerous biological processes, including va-sodilatation, neurotransmission and macrophage-mediated immunity. The family of nitric oxide synthases (NOS) comprises inducible NOS (iNOS), endothelial NOS (eNOS), and neuronal NOS (nNOS). Interestingly, various studies have shown that all three isoforms can be involved in promoting or inhibiting the etiology of cancer. NOS activity has been detected in tumour cells of various histogenetic origins and has been associated with tumour grade, proliferation rate and expression of important signaling components associated with cancer development such as the oestrogen receptor. It appears that high levels of NOS expression (for example, generated by activated macrophages) may be cytostatic or cytotoxic for tumor cells, whereas low level activity can have the opposite effect and promote tumour growth. Paradoxically therefore, NO (and related reactive nitrogen species) may have both genotoxic and angiogenic pro     

Studies of Blastocystis hominis

Blastocystis hominis, grown in Boeck-Drbohlav culture medium, modified by the omission of rice starch and the addition of 20% human serum and mineral oil cover to the Locke's solution overlay, can assume 3 morphologic forms. In the absence of human serum the vacuolated form, which divides by binary fission predominates. In medium with high serum content the granular form appears, with 3 types of granules. Spheroid or more elongate cytoplasmic granules predominate. In older organisms, lipid granules are found either in the peripheral cytoplasm or in the central vacuolar space. In occasional cells, variable numbers of reproductive granules develop in the central vacuolar space. These latter granules are released from the organism and give rise to typical B. hominis cells. The 3rd form, the ameba form, appears in small numbers in older cultures and in those treated with antibiotics. Ameba forms feed on bacteria and have slow pseudopodial activity. Exposure to oxygen causes rapid damage to cell membrane, with resulting leakage and collapse.