Loss of planktotrophy and speciation: geographical fragmentation in the deep-water gastropod genus Bathytoma (Gastropoda,Conoidea) in the western Pacific

Dispersal capabilities are crucial in how speciation patterns are determined in marine invertebrates. Species possessing a long-living planktonic larva apparently have a dispersal advantage over those with non-planktotrophic development, and their distant populations may exchange genetic material, maintaining a broad geographical range for the species. Recent species of the gastropod genus Bathytoma (Conoidea) are all characterized by non-planktotrophic development, having most probably lost a free-swimming larva in the pre-Pliocene, as Miocene fossils have protoconchs indicating planktotrophic larval development. All have a bathyal distribution (100–1500 m), which implies that their capability for direct expansion on the bottom is restricted by both deep-sea basins and shallow-water areas, especially in insular West and South-West Indo-Pacific. Therefore, it can be hypothesized that Bathytoma populations should represent numerous, mostly allopatric taxa restricted to a single or contiguous island groups. We tested this hypothesis using molecular and morphological characters independently. One hundred and thirty-eight specimens from the Philippines, Solomons, Vanuatu, and the Coral Sea were sequenced for one mitochondrial (COI) and one nuclear (ITS2) gene, and 14 operational molecular units were recognized. When these molecular units are overlaid over shell characters, 13 species (11 unnamed) and one form of uncertain status are recognized: three occur in the Philippines, six in the Solomons and one in New Caledonia. Broad distributions (inter-archipelagic) are uncommon (three species). On the whole, the phylogeographic pattern of the diversity in the genus is rather complex and probably also reflects processes of sympatric and fine-scale allopatric speciation, and local extinctions. The eleven new species are described and named.     

Diverse historical processes shape deep phylogeographical divergence in the pollinating seed parasite Greya politella

Understanding the historical framework in which species interactions have diversified across landscapes may help to partition the effects of vicariance and geographically variable selection in shaping the geographical mosaic of coevolving species. We used phylogeographical analyses of the pollinating seed parasite Greya politella (Lepidoptera: Prodoxidae) to define the historical processes that may have structured interactions of this species with its host plants across major biogeographical breaks in western North America. Using 648 bp of cytochrome oxidase I and amplified fragment length polymorphisims, we identified deep genetic breaks among some populations consistent with some definitions of cryptic species. A combination of phylogenetic and population genetic approaches indicates that different historical processes may have structured G. politella genetic diversity in four regions: northern Pacific Northwest, southern Oregon, southern Sierra Nevada, and the remainder of California. The northern Pacific Northwest had high genetic diversity likely due to glacial refugia and subsequent spatial expansion, concordant with some other taxa. Populations in southern Oregon possessed unique, closely related haplotypes with restricted gene flow, possibly indicating a long-standing set of populations in this endemic-rich region. Analyses of California populations showed evidence of restricted gene flow and spatial expansion with many closely related haplotypes that occupy a broad geographical range. Southern Sierra Nevada populations were genetically distinct and highly diverse, possibly due to a localized glacial refugium. Together, these results suggest that vicariance and population expansion, possibly in combination with geographically variable selection, have shaped the diversification of G. politella and its interactions with its host plants.     

Synthesis of γ-Glutamyldopamine and Other Peptidoamines in the Nervous System of Aplysia californica

The synthesis of a series of gamma-glutamyl amines (gamma-Glu-amines), including gamma-Glu-dopamine, gamma-Glu-5-hydroxytryptamine, gamma-Glu-octopamine, gamma-Glu-tryptamine, gamma-Glu-tyramine, and gamma-Glu-phenylethylamine, by nervous tissue of the marine mollusc Aplysia californica is described. After ganglia were incubated in vitro with 14C-amines, the unchanged amine and a new 14C-labeled product, identified as the gamma-Glu conjugate of the amine, were isolated from the tissue extracts. Identification was made by comparing the chromatographic properties (HPLC, TLC, and LC) of the isolated conjugates with chemically synthesized gamma-Glu-amines before and after acid hydrolysis.     

Deep genetic divergence in the darkling beetle Pimelia rugulosa (Coleoptera,Tenebrionidae) reflects Plio‐Pleistocenic paleogeographic history of Sicily

The genus Pimelia is represented in Sicily by the two species P. grossa and P. rugulosa, the latter with the two subspecies P. r. rugulosa and P. r. sublaevigata. A third subspecies, P. r. apula, is present only in Puglia. The phylogeographic history of this genus in Sicily was reconstructed using sequences of the complete cox2 gene, applying phylogenetic and molecular dating methods. Phylogenetic analysis confirmed the monophyly of the two species, as well as the subdivision of P. rugulosa in the three morphological subspecies. One previously undetected and deeply divergent lineage was described that is geographically related to the Hyblean massif. It is therefore suggested that the deep divergence of the two major P. rugulosa clades in Sicily reflects an ancient separation between the Hyblean massif and the other land masses of Sicily. Dating analysis confirmed that the timing of P. rugulosa genetic divergence is compatible with the formation of the Hyblean massif. Furthermore, P. rugulosa populations of the Hyblean massif, whose taxonomy has been historically problematic, display levels of genetic divergence comparable to those observed at the species level. The possibility that this new lineage might deserve species rank is presented.     

αγ-Enolase in the Rat: Ontogeny and Tissue Distribution

Abstract: The rat brain enolases are dimers composed of α and γ subunits. At pH 8.6 αγ-enolase seemed to be stable, and no evidence was found for the possible formation of αγ-enolase from αα-enolase and γγ-enolase in the course of rat brain homogenization. During ontogeny of the rat forebrain, αγ-enolase was formed before γγ-enolase. The half-maximal specific concentrations were reached at postnatal days 14 and 23, respectively. The distribution of αγ- and γγ-enolase in various rat brain areas was also investigated. In all areas both forms were present. In neuroendocrine tissues αγ-enolase was present at a much higher concentration than γγ-enolase. The ratio between γγ-enolase and αγ-enolase may be indicative of the degree of neuronal maturation, a conclusion further substantiated by the high ratio observed in cerebellum and the low ratio observed in olfactory bulbs, both compared with the ratio in forebrain.     

Gamma-glutamyl-gamma-aminobutyrate hydrolase in the putrescine utilization pathway of Escherichia coli K-12

gamma-Glutamyl-gamma-aminobutyrate hydrolase (PuuD) was purified and the properties of the enzyme were characterized. The active center of PuuD was identified as Cys-114 by site-directed mutagenesis. The expression of PuuD was induced by putrescine and O2 (substrates of the Puu pathway), while the addition of succinate or NH4Cl (products of the Puu pathway) to the medium reduced the expression of PuuD. The findings that the puuD-deficient strain accumulated gamma-glutamyl-gamma-aminobutyrate (gamma-Glu-GABA) and could not grow on putrescine as a sole nitrogen source indicate that PuuD is physiologically important as a gamma-Glu-GABA hydrolase.     

GYMNODINIUM ACIDOTUM NYGAARD (PYRROPHYTA), A DINOFLAGELLATE WITH AN ENDOSYMBIOTIC CRYPTOMONAD1

Ultrastructural examination of the freshwater, blue-green dinoflagellate Gymnodinium acidotum Nygaard revealed the presence of an endosymbiotic cryptomonad. Features of the endosymbiont allying it with the Cryptophyceae include mitochondria with flattened cristae, paired thylakoids with electron-dense contents, and nucleomorphs, bodies unique to the Cryptophyceae. This report is the first conclusive documentation of a symbiosis involving these two groups.     

Increased levels of gamma-glutamylamines in Huntington disease CSF

Transglutaminases (TGases) catalyze several reactions with protein substrates, including formation of γ-glutamyl-ε-lysine cross-links and γ-glutamylpolyamine residues. The resulting γ-glutamylamines are excised intact during proteolysis. TGase activity is altered in several diseases, highlighting the importance of in situ enzymatic determinations. Previous work showed that TGase activity (as measured by an in vitro assay) and free γ-glutamyl-ε-lysine levels are elevated in Huntington disease (HD) and that γ-glutamyl-ε-lysine is increased in HD CSF. Although free γ-glutamyl-ε-lysine was used in these studies as an index of in situ TGase activity, γ-glutamylpolyamines may also be diagnostic. We have devised methods for the simultaneous determination of four γ-glutamylamines in CSF: γ-glutamyl-ε-lysine, γ-glutamylspermidine, γ-glutamylputrescine, and bis-γ-glutamylputrescine and showed that all are present in normal human CSF at concentrations of ∼150, 670, 40, and 240 nM, respectively. The high γ-glutamylspermidine/γ-glutamylputrescine and γ-glutamylspermidine/bis-γ-glutamylputrescine ratios presumably reflect in part the large spermidine to putrescine mole ratio in human brain. We also showed that all four γ-glutamylamines are elevated in HD CSF. Our findings support the hypotheses that (i) γ-glutamylpolyamines are reflective of TGase activity in human brain, (ii) polyamination is an important post-translational modification of brain proteins, and (iii) TGase-catalyzed modification of proteins is increased in HD brain.