One new species of free-living marine nematode from the Yellow Sea, China.

A new species of Setostephanolaimus Tchesunov, 1994, S. longiseta sp. nov. was discovered in an intertidal sand beach along the Rizhao coast of the Yellow Sea. It is characterized by its long and slender body, long cephalic setae (longer than 20 m and 16 m in males and females, respectively) and subcephalic setae, long spicules (longer than 90 m), gubernaculum with dorsal hooked apophyses, along with presence of 1012 tubular precloacal supplements in males. Updated dichotomous key for species of the genus Setostephanolaimus is also given.

Homology modeling and virtual screening for inhibitors of lipid kinase PI(4)K from Plasmodium.

Malaria parasite strains have emerged to tolerate the therapeutic effects of the prophylactics and drugs presently available. Recent studies have shown that KAI715 and its analogs inhibit malaria parasites growth by binding to lipid kinase PI(4)K (phosphatidylinositol-4-OH kinase) of the parasites. Therefore, targeting PI(4)K may open up new avenues of target-based drug discovery to identify novel anti-malaria drugs. In this investigation, we describe the discovery of novel potent PfPI(4)K (PI(4)K from P. falciparum) inhibitors by employing a proposed hybrid virtual screening (VS) method, including pharmacophore model, drug-likeness prediction and molecular docking approach. 3D structure of PfPI(4)K has been established by homology modeling. Pharmacophore model HypoA of PfPI(4)K inhibitors has been developed based on the ligand complexed with its corresponding receptor. 174 compounds with good ADMET properties were carefully selected by a hybrid virtual screening method. Finally, the 174 hits were further validated by using a new pharmacophore model HypoB built based on the docking pose of BQR685, and 95 compounds passed the last filter. These compounds would be further evaluated by biological activity assays. The molecular interactions of the top two potential inhibitors with the active site residues are discussed in detail. These identified hits can be further used for designing the more potent inhibitors against PfPI(4)K by scaffold hopping, and deserve consideration for further structure-activity relationship (SAR) studies.

Specific impact of tobamovirus infection on the Arabidopsis small RNA profile.

Tobamoviruses encode a silencing suppressor that binds small RNA (sRNA) duplexes in vitro and supposedly in vivo to counteract antiviral silencing. Here, we used sRNA deep-sequencing combined with transcriptome profiling to determine the global impact of tobamovirus infection on Arabidopsis sRNAs and their mRNA targets. We found that infection of Arabidopsis plants with Oilseed rape mosaic tobamovirus causes a global size-specific enrichment of miRNAs, ta-siRNAs, and other phased siRNAs. The observed patterns of sRNA enrichment suggest that in addition to a role of the viral silencing suppressor, the stabilization of sRNAs might also occur through association with unknown host effector complexes induced upon infection. Indeed, sRNA enrichment concerns primarily 21-nucleotide RNAs with a 5'-terminal guanine. Interestingly, ORMV infection also leads to accumulation of novel miRNA-like sRNAs from miRNA precursors. Thus, in addition to canonical miRNAs and miRNA*s, miRNA precursors can encode additional sRNAs that may be functional under specific conditions like pathogen infection. Virus-induced sRNA enrichment does not correlate with defects in miRNA-dependent ta-siRNA biogenesis nor with global changes in the levels of mRNA and ta-siRNA targets suggesting that the enriched sRNAs may not be able to significantly contribute to the normal activity of pre-loaded RISC complexes. We conclude that tobamovirus infection induces the stabilization of a specific sRNA pool by yet unknown effector complexes. These complexes may sequester viral and host sRNAs to engage them in yet unknown mechanisms involved in plant:virus interactions.

Validation of microtubule-associated Tobacco mosaic virus RNA movement and involvement of microtubule-aligned particle trafficking.

Functional studies of Tobacco mosaic virus (TMV) infection using virus derivatives expressing functional, dysfunctional, and temperature-sensitive movement protein (MP) mutants indicated that the cell-to-cell transport of TMV RNA is functionally correlated with the association of MP with microtubules. However, the role of microtubules in the movement process during early infection remains unclear, since MP accumulates on microtubules rather late in infection and treatment of plants with microtubule-disrupting agents fails to strongly interfere with cell-to-cell movement of TMV RNA. To further test the role of microtubules in TMV cell-to-cell movement, we investigated TMV strain Ni2519, which is temperature-sensitive for movement. We demonstrate that the temperature-sensitive defect in movement is correlated with temperature-sensitive changes in the localization of MP to microtubules. Furthermore, we show that during early phases of recovery from non-permissive conditions, the MP localizes to microtubule-associated particles. Similar particles are found in cells at the leading front of spreading TMV infection sites. Initially mobile, the particles become immobile when MP starts to accumulate along the length of the particle-associated microtubules. Our observations confirm a role for microtubules in the spread of TMV infection and associate this role with microtubule-associated trafficking of MP-containing particles in cells engaged in the cell-to-cell movement of the TMV genome.