Characterization of tetranucleotide microsatellite loci and development and validation of multiplex reactions for the study of right whale species (genus Eubalaena)

A North Atlantic right whale (Eubalaena glacialis) genomic library was developed and screened with a (GATA)₈ probe to identify tetranucleotide microsatellite loci. Sixteen characterized loci were polymorphic in North Atlantic and/or South Atlantic (Eubalaena australis) right whales, 12 being polymorphic in E. glacialis, and 15 in E. australis. Fourteen of these were combined with 21 other previously identified loci for a suite of 35 loci which can be used to increase resolution of genetic analyses of these species. Multiplex reactions were developed for genotyping samples at these loci, providing a method that is rapid, reliable and cost‐effective.     

Cannibalism and Coprophagy Are Modes of Transmission of Blastocrithidia triatomae (Trypanosomatidae) between Triatomines

Transovarial transmission was not detectable among Blastocrithidia triatomae- infected Triatoma infestans . Rather, B. triatomae was transmitted directiy between triatomines by cannibalism and coprophagy. Cannibalism conditions that excluded coprophagy always resulted in an infection of Dipetalogaster maxima . The efficiency of transmission was not influenced by the blood source—mice or chickens—fed to the infected donor bugs although chicken blood lyses the epimastigotes of the stomach population. Triatoma infestans was infected by coprophagy only if fed, not if unfed. Blastocrithidia triatomae in dry feces was taken up only if the feces were redissolved in fresh feces. Infections also appeared in groups of bugs fed on chickens previously used for feeding infected bugs.     

Coelenterate Neuropeptides: Structure, Action and Biosynthesis

Evolutionary "old" nervous systems such as those of coelenteratesare peptidergic: Using various radioimmunoassays we have nowisolated 13 novel neuropeptides from sea anemones and severalothers from hydrozoan polyps and medusae. These peptides areall structurally related and contain the C-terminal sequenceArg-X-NH₂ or Lys-X-NH₂, where X is Ala, Asn, Ile, Phe, Pro orTrp. Three neuropeptides have a novel N-terminal L-3-phenyllactylresidue, which protects against degradation by nonspecific aminopeptidases.The neuropeptides from sea anemones are produced by differentsets of neurones and have excitatory or inhibitory actions onisolated muscle preparations, suggesting that they are neurotransmittersor neuromodulators. We have also cloned the precursor proteinfor the sea-anemone neuropeptide Antho-RFamide (<Glu-Gly-Arg-Phe-NH₂).In Calliactis parasitica this precursor harbours 19 copies ofimmature Antho-RFamide (Gln-Gly-Arg-Phe-Gly) together with 7other, putative neuropeptide sequences. The precursor of Anthopleuraelegantissima contains 14 copies of Antho-RFamide and 19 other,putative neuropeptides. This shows that the biosynthetic machineryfor neuropeptides in coelenterates, the lowest animal grouphaving a nervous system, is already very efficient and similarto that of higher invertebrates, such as molluscs and insects,and vertebrates.     

Improved detection of iris severe mosaic virus in secondarily-infected iris bulbs

The influence of wounding and high-temperature treatment on the detection of iris severe mosaic virus (ISMV) in secondarily ISMV-infected iris bulbs was studied. Wounding of the bulbs just after lifting, followed by storage for 3 wk at 17°C or 20°C, increased the detectability of ISMV to 100% reliability. High-temperature treatment and consecutive storage at 17°C induced a similar improvement of detection. It is concluded that a certain degree of stress, such as wounding or high-temperature treatment, ultimately leads to an increase in viral antigens and thus to improvement of detection. It is hypothesised that the virus titre increases by the altered metabolism during the repair reactions as a response to stress applied to the bulbs.     

Phylogenetic analysis of Nymphaeales using fast-evolving and noncoding chloroplast markers

The Nymphaeales (water-lilies and relatives) represent one of the earliest branching lineages of angiosperms and comprise about 70 aquatic species. Here, we present a comprehensive study of phylogenetic relationships within the Nymphaeales from a dataset containing 24 representatives of the order, including all currently recognized genera and all subgenera of the genus Nymphaea , plus 5 outgroup taxa. Nine different regions of the chloroplast genome − comprising spacers, group II introns, a group I intron, and a protein coding gene − were analysed. This resulted in a character matrix of 6597 positions and an additional 369 characters obtained from coded length mutations. Maximum parsimony and Bayesian analyses of the complete dataset yielded congruent, fully resolved and well-supported trees. Our data confirm the monophyly of the Cabombaceae but do not provide convincing support for the monophyly of Nymphaeaceae with respect to Nuphar . Moreover, the genus Nymphaea is inferred to be paraphyletic with respect to Ondinea , Victoria and Euryale . In fact, the Australian endemic Ondinea forms a highly supported clade with members of the Australian Nymphaea subgenus Anecphya . In addition, Victoria and Euryale are inferred to be closely related to a clade comprising all night-blooming water-lilies ( Nymphaea subgenera Hydrocallis and Lotos ). An experimental approach showed taxon sampling to be of influence on the nodes reconstructed in core Nymphaeaceae. The results underscore that more diverse genera, if not clearly known to be monophyletic, should be represented by all major lineages.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 154 , 141–163.     

Heme Proteins in Sulfide-oxidizing Bacteri/Mollusc Symbioses

SYNOPSIS. A number of bivalve mollusc species in the familiesVesicomyidae, Lucinidae and Solemyidae from sulfide-rich sedimentsharbor sulfide-oxidizing bacteria as intracellular symbiontsin gills. Cytoplasmic hemoglobin, relatively uncommon in symbiont-freegills, is a nearly constant feature in these symbiont-harboringbivalve gills and may function in the delivery of oxygen andsulfide to ensure symbiont autotrophy and host cell respiration.However, biochemical characteristics of isolated hemoglobinsfrom these species differ vastly. For example, within clamsof the same genus, gill hemoglobin concentrations vary frommicromolar to millimolar. Ligand reaction rate constants ofmultiple gill hemoglobins from a single species differ by threeorders of magnitude. Gill hemoglobins from congeners form differentderivatives in the presence of sulfide. Some hemoglobins reactavidly with hydrogen sulfide while others appear refractory.This assortment of characteristics suggests that the role ofhemoglobin in each symbiotic association cannot be generalized.     

Transient over-expression of barley BAX Inhibitor-1 weakens oxidative defence and MLA12-mediated resistance to Blumeria graminis f.sp. hordei

BAX Inhibitor-1 (BI-1) is a conserved cell death suppressor protein. In barley, BI-1 ( HvBI-1 ) expression is induced upon powdery mildew infection and when over-expressed in epidermal cells of barley, HvBI-1 induces susceptibility to the biotrophic fungal pathogen Blumeria graminis . We co-expressed mammalian pro-apoptotic BAX together with HvBI-1, and the mammalian BAX antagonist BCL-X_L in barley epidermal cells. BAX expression led to cessation of cytoplasmic streaming and collapse of the cytoplasm while co-expression of HvBI-1 and BCL-X_L partially or completely, respectively, rescued cells from BAX lethality. When B. graminis was attacking epidermal cells, a green fluorescent protein fusion of HvBI-1 accumulated at the site of attempted penetration and was also present around haustoria. Over-expression of HvBI-1 in epidermal cells weakened a cell-wall-associated local hydrogen peroxide burst in a resistant mlo -mutant genotype and supported haustoria accommodation in race-specifically resistant MLA12 -barley. HvBI-1 is a cell death regulator protein of barley with the potential to suppress host defence reactions.