Looking for a 5-HT7 radiotracer for positron emission tomography

In search of a serotonin 5-HT₇ radiotracer for positron emission tomography, we developed 1-{2-[(2S)-1-(phenylsulfonyl)pyrrolidin-2-yl]ethyl}piperidin-4-yl 4-fluorobenzoate. After labeling in good yield with fluorine-18 via nitro for fluorine exchange, preliminary biological experiments with autoradiographies failed to evidence any specific 5-HT₇ receptor delineation.     

Development and evaluation of a 68Ga labeled pamoic acid derivative for in vivo visualization of necrosis using positron emission tomography

In this study, we labeled N,N′-bis(diethylenetriamine pentaacetic acid)-pamoic acid bis-hydrazide (bis-DTPA-PA) with the generator produced PET radionuclide gallium-68 and evaluated ⁶⁸Ga-bis-DTPA-PA as a potential tracer for in vivo visualization of necrosis by positron emission tomography (PET). Radiolabeling was achieved with a decay-corrected radiochemical yield of 63%. Biodistribution and in vivo stability studies in normal mice showed that ⁶⁸Ga-bis-DTPA-PA is cleared faster from normal tissue than the previously reported ^99mTc(CO)₃ complex with bis-DTPA-PA which on the other hand is more stable in vivo. ⁶⁸Ga-bis-DTPA-PA showed a 3.5–5 times higher binding to necrotic tissue than to viable tissue as shown by in vitro autoradiography while no statistically significant increased hepatic uptake was found in a biodistribution study in a mouse model of hepatic apoptosis. Specificity and avidity for necrosis was further evaluated in rats with a reperfused partial liver infarction and ethanol induced muscular necrosis. Dynamic microPET images showed a fast and prolonged uptake of ⁶⁸Ga-bis-DTPA-PA in necrotic tissue with in vivo and ex vivo images correlating well with histochemical stainings. With necrotic to viable tissue activity ratios of 8–15 on ex vivo autoradiography, depending on the necrosis model, ⁶⁸Ga-bis-DTPA-PA showed a faster and higher uptake in necrotic tissue than the ^99mTc(CO)₃ analog. These results show that ⁶⁸Ga-bis-DTPA-PA specifically binds to necrotic tissue and is a promising tracer for in vivo visualization of necrosis using PET.     

Heat shock proteins protect platyfish (Xiphophorus maculatus) from Yersinia ruckeri induced mortality

The significant disadvantages accompanied with the use of antibiotics in aquaculture, emphasize the need for developing alternative disease control strategies, like novel vaccine approaches and immunostimulating measures. Several studies have already pointed out the ability of heat shock proteins (HSPs) to modulate innate and adaptive immune responses, what makes them potent candidates for the development of a new disease prevention method. In this study, the use of self and non-self heat shock proteins as a new prophylactic treatment against bacterial diseases in freshwater aquaculture was investigated. Therefore, an infection model was developed with platyfish as a host for Yersinia ruckeri infections. In this infection model, the effect of different treatments with HSPs on the survival of the fish after bacterial infection was tested: non-lethal heat shock, intracoelomal injection with two recombinant bacterial HSPs, GroEL and DnaK, and a combination of a non-lethal heat shock and an injection with bacterial HSPs. The results show that a non-lethal heat shock could not protect fish against a subsequent infection with Y. ruckeri. However, when the fish received an injection with bacterial HSPs, Y. ruckeri induced mortality was reduced. This effect became significant when the administration of bacterial HSPs was combined with a non-lethal heat shock. These data suggest a possible role for heat shock proteins as an immunostimulating treatment in fish against bacterial infections.     

Microcostatus schoemanii sp. nov., M. cholnokyi sp. nov. and M. angloensis sp. nov. three new terrestrial diatoms (Bacillariophyceae) from South Africa

The terrestrial diatom Microcostatus schoemanii sp. nov. is described from dry soils of the Faan Meintjies Nature Reserve (North‐West Province, South Africa). Microcostatus cholnokyi sp. nov. and Microcostatus angloensis sp. nov. are described from sandy soils at a colliery near the town of Kriel (Mpumalanga Province, South Africa). The morphology of these taxa is examined using both light and scanning electron microscopy and new taxa are compared with similar species. In M. schoemanii the density of the striae combined with the valve outline and the distance between the central raphe endings are the main distinguishing morphological features. M. cholnokyi is differentiated by the presence of a conopeum and the distinct structure of the microcostae. M. angloensis is similar to M. schoemanii but differentiated by the shape of the cell and the apices, the angle of striation and the distance in between the proximal raphe endings.     

Suppression of melon fly (Diptera: Tephritidae) populations with releases of Fopius arisanus and Psyttalia fletcheri (Hymenoptera: Braconidae) in North Shore Oahu, HI, USA

Field experiments and surveys were conducted to evaluate the efficacy of releasing Fopius arisanus (Sonan) and Psyttalia fletcheri (Silvestri) parasitoids for suppression of Bactrocera cucurbitae (Coquillett) infesting wild Coccinia grandis L. In 2003 and 2004, P. fletcheri releases combined with natural emergence from wild fly populations resulted in better fly suppression, compared to the control site. While P. fletcheri developed freely on melon fly, F. arisanus was less successful at producing its own progeny, yet causing mortality and a twofold decrease in pupae recovered from ivy gourds. Concurrent releases of both parasitoids exerted a compounded suppressive effect on the melon fly population 2–3 times higher than during the pre-release phase. A similar, less obvious, pattern occurred in 2004, due to reduction of the ivy gourd fruit canopy. In 2005, only P. fletcheri was released, with greatly reduced impact, due to ivy gourd destruction and by growers leaving crop culls in fields, producing large numbers of melon flies unaffected by parasitoid releases.     

Historical biogeography of the land snail <Emphasis Type="Italic">Cornu aspersum</Emphasis>: a new scenario inferred from haplotype distribution in the Western Mediterranean basin

Background  

Despite its key location between the rest of the continent and Europe, research on the phylogeography of north African species remains very limited compared to European and North American taxa. The Mediterranean land mollusc Cornu aspersum (= Helix aspersa) is part of the few species widely sampled in north Africa for biogeographical analysis. It then provides an excellent biological model to understand phylogeographical patterns across the Mediterranean basin, and to evaluate hypotheses of population differentiation. We investigated here the phylogeography of this land snail to reassess the evolutionary scenario we previously considered for explaining its scattered distribution in the western Mediterranean, and to help to resolve the question of the direction of its range expansion (from north Africa to Europe or vice versa). By analysing simultaneously individuals from 73 sites sampled in its putative native range, the present work provides the first broad-scale screening of mitochondrial variation (cyt b and 16S rRNA genes) of C. aspersum.     

Functional conservation of a forebrain enhancer from the elephant shark (<Emphasis Type="Italic">Callorhinchus milii</Emphasis>) in zebrafish and mice

Background  

The phylogenetic position of the elephant shark (Callorhinchus milii ) is particularly relevant to study the evolution of genes and gene regulation in vertebrates. Here we examine the evolution of Dlx homeobox gene regulation during vertebrate embryonic development with a particular focus on the forebrain. We first identified the elephant shark sequence orthologous to the URE2 cis -regulatory element of the mouse Dlx1/Dlx2 locus (herein named CmURE2). We then conducted a comparative study of the sequence and enhancer activity of CmURE2 with that of orthologous regulatory sequences from zebrafish and mouse.     

A member of a new plant gene family encoding a meprin and TRAF homology (MATH) domain-containing protein is involved in restriction of long distance movement of plant viruses

Restriction of long distance movement of several potyviruses in Arabidopsis thaliana is controlled by at least three dominant restricted TEV movement (RTM) genes, named RTM1, RTM2 and RTM3 and acts as a non-conventional resistance. RTM1 encodes a protein belonging to the jacalin family and RTM2 encodes a protein which has similarities to small heat shock proteins. The recent cloning of RTM3 which encodes a protein belonging to an unknown protein family of 29 members that has a meprin and TRAF homology (MATH) domain in its N-terminal region and a coiled-coil (CC) domain at its C-terminal end is an important breakthrough for a better understanding of this resistance process. Not only the third gene involved in this resistance has been identified and has allowed revealing a new gene family in plant but the discovery that the RTM3 protein interacts directly with RTM1 strongly suggests that the RTM proteins form a multimeric complex. However, these data also highlight striking similarities of the RTM resistance with the well known R-gene mediated resistance.Key words: plant virus, potyvirus, resistance, long distance movement, RTM genes, Arabidopsis thaliana