The peculiar nemertean larva pilidium recurvatum belongs to Riserius sp., a basal heteronemertean that eats Carcinonemertes errans,a hoplonemertean parasite of Dungeness crab

A typical nemertean pilidium larva resembles a hat with ear flaps. But one type, called pilidium recurvatum, looks more like a sock, swimming heel first. This distinctive larva was discovered in 1883 off the coast of Rhode Island and subsequently found in plankton samples from other parts of the world. Despite the long time since discovery, and its significance in discussions of larval evolution, this larva remained unidentified even to the family level. We collected pilidium recurvatum larvae from plankton samples in Coos Bay, OR, and identified them as belonging to the heteronemertean genus Riserius based on juvenile morphology and DNA sequence data. Phylogenetic analysis suggests that two distinct types of pilidium recurvatum from Oregon represent two new species within this currently monotypic genus. We describe the morphology of pilidium recurvatum using confocal microscopy and compare it to that of the typical pilidium, discussing possible implications for larval feeding. We also report our surprising discovery that juveniles of Riserius sp. from Oregon prey on another nemertean, Carcinonemertes errans, an egg predator of Cancer magister (Dungeness crab), a commercially important species. We speculate that the species‐level diversity and geographic distribution of Riserius may be much greater than currently appreciated.     

The discovery and optimization of naphthalene-linked P2-P4 Macrocycles as inhibitors of HCV NS3 protease

Naphthalene-linked P2-P4 macrocycles within a tri-peptide-based acyl sulfonamide chemotype have been synthesized and found to inhibit HCV NS3 proteases representing genotypes 1a and 1b with single digit nanomolar potency. The pharmacokinetic profile of compounds in this series was optimized through structural modifications along the macrocycle tether as well as the P1 subsite. Ultimately a compound with oral bioavailability of 100% in rat, and a long half-life in plasma was obtained. However, compounds in this macrocyclic series exhibited cardiac effects in an isolated rabbit heart model and for this reason further optimization efforts were discontinued.     

Host habitat assessment by a parasitoid using fungal volatiles

Background

The genus Mantella, endemic poison frogs of Madagascar with 16 described species, are known in the field of international pet trade and entered under the CITES control for the last four years. The phylogeny and phylogeography of this genus have been recently subject of study for conservation purposes. Here we report on the studies of the phylogeography of the Mantella cowani group using a fragment of 453 bp of the mitochondrial cytochrome b gene from 195 individuals from 21 localities. This group is represented by five forms: M. cowani, a critically endangered species, a vulnerable species, M. haraldmeieri, and the non-threatened M. baroni, M. aff. baroni, and M. nigricans.

Results

The Bayesian phylogenetic and haplotype network analyses revealed the presence of three separated haplotype clades: (1) M. baroni, M. aff. baroni, M. nigricans, and putative hybrids of M. cowani and M. baroni, (2) M. cowani and putative hybrids of M. cowani and M. baroni, and (3) M. haraldmeieri. The putative hybrids were collected from sites where M. cowani and M. baroni live in sympatry.

Conclusion

These results suggest (a) a probable hybridization between M. cowani and M. baroni, (b) a lack of genetic differentiation between M. baroni/M. aff. baroni and M. nigricans, (c) evidence of recent gene-flow between the northern (M. nigricans), eastern (M. baroni), and south-eastern (M. aff. baroni) forms of distinct coloration, and (d) the existence of at least three units for conservation in the Mantella cowani group.     

Differentiation of Dasheen Mosaic Potyvirus Isolates Based on Variability in the Apparent Size of the Capsid Protein in Western Blots

The capsid protein (CP) sizes of seven dasheen mosaic virus (DsMV) isolates and one isolate of vanilla mosaic virus were estimated to be 38–47 kDa and 47 kDa, respectively, based on Western blot analyses using DsMV polyclonal antiserum. The CP sizes of 12 other potyviruses were estimated to be 31–36 kDa. Apparent CP sizes of the DsMV isolates extracted from their original hosts were 47 kDa ( Xanthosoma caracu ), 45 kDa ( Colocasia esculenta , Zantedeschia aethiopica ), and 38–46 kDa ( Caladium hortulanum ). Propagation in seedlings of Philodendron selloum did not affect the CP sizes of any of the individual DsMV isolates. The same characteristic CP sizes were also detected in Western blot analyses of these isolates, using polyclonal antisera of eight other potyviruses, or using Agdia Poty 1 monoclonal antiserum, and using three monoclonal antisera of papaya ringspot virus type W. The apparent CP size and pattern of apparent breakdown products as revealed by Western blots of extracts from infected aroids may be used in the characterization and differentiation of DsMV isolates.     

Nucleotide sequence analysis of the human salivary protein genes HIS1 and HIS2, and evolution of the STATH/HIS gene family

Human histatins are a family of low-M(r), neutral to very basic, histidine-rich salivary polypeptides. They probably function as part of the nonimmune host defense system in the oral cavity. A 39-kb region of DNA containing the HIS1 and HIS2 genes was isolated from two human genomic phage libraries as a series of overlapping clones. The nucleotide sequences of the HIS1 gene and part of the HIS2(1) gene were determined. The transcribed region of HIS1 spans 8.5 kb and contains six exons and five introns. The HIS1 and HIS2(1) genes exhibit 89% overall sequence identity, with exon sequences exhibiting 95% identity. The two loci probably arose by a gene duplication event approximately 15-30 Mya. The HIS1 sequence data were also compared with that of STATH. Human statherin is a low-M(r) acidic phosphoprotein that acts as an inhibitor of precipitation of calcium phosphate salts in the oral cavity. The HIS1 and STATH genes show nearly identical overall gene structures. The HIS1 and STATH loci exhibit 77%-81% sequence identity in intron DNA and 80%-88% sequence identity in noncoding exons but only 38%-43% sequence identity in the protein-coding regions of exons 4 and 5. These unusual data suggest that HIS1, HIS2, and STATH belong to a single gene family exhibiting accelerated evolution between the HIS and STATH coding sequences.