Disruption of microtubule organization and centrosome function by expression of tobacco mosaic virus movement protein

The movement protein (MP) of Tobacco mosaic virus mediates the cell-to-cell transport of viral RNA through plasmodesmata, cytoplasmic cell wall channels for direct cell-to-cell communication between adjacent cells. Previous in vivo studies demonstrated that the RNA transport function of the protein correlates with its association with microtubules, although the exact role of microtubules in the movement process remains unknown. Since the binding of MP to microtubules is conserved in transfected mammalian cells, we took advantage of available mammalian cell biology reagents and tools to further address the interaction in flat-growing and transparent COS-7 cells. We demonstrate that neither actin, nor endoplasmic reticulum (ER), nor dynein motor complexes are involved in the apparent alignment of MP with microtubules. Together with results of in vitro coprecipitation experiments, these findings indicate that MP binds microtubules directly. Unlike microtubules associated with neuronal MAP2c, MP-associated microtubules are resistant to disruption by microtubule-disrupting agents or cold, suggesting that MP is a specialized microtubule binding protein that forms unusually stable complexes with microtubules. MP-associated microtubules accumulate ER membranes, which is consistent with a proposed role for MP in the recruitment of membranes in infected plant cells and may suggest that microtubules are involved in this process. The ability of MP to interfere with centrosomal gamma-tubulin is independent of microtubule association with MP, does not involve the removal of other tested centrosomal markers, and correlates with inhibition of centrosomal microtubule nucleation activity. These observations suggest that the function of MP in viral movement may involve interaction with the microtubule-nucleating machinery.     

Identification, sequencing, and enzymatic activity of the erythrose-4-phosphate dehydrogenase gene of Vibrio cholerae.

We have identified a gene in Vibrio cholerae (epd) which encodes an erythrose-4-phosphate dehydrogenase activity and is located immediately downstream of an iron-regulated virulence gene, irgA, and immediately upstream of a gene encoding phosphoglycerate kinase (pgk). Expression of epd in V. cholerae is not regulated by iron, nor is it required for virulence in an infant mouse model.     

Rostellar apparatus of Fernandezia spinosissima (von Linstow, 1894) (Cestoda, Cyclophyllidea, Davaineidae): microanatomy and fine structure

The rostellar apparatus of Fernandezia spinosissima is examined by light and transmission electron microscopy. It is described as composed of rostellum, pseudoproboscis, and two groups of glandular syncytia, one in the rostellum and the other inwards to the rostellum and the pseudoproboscis. The rostellum is a discoid cushion with muscular walls. There are numerous thin vertical muscular fibres and glandular syncytia inside it. Its tegument has slender microtriches. Peripherally, the rostellum is encircled by thin muscle fibres that protrude anteriorly between rostellar hooks and group posteriorly to form retractors. The rostellar hook guards are associated with a complicated network of muscles and nerves. The pseudoproboscis is a thick-walled ring around the apical part of the scolex adjacent to the rostellum. Its tegument has microtriches with modified spines that are interpreted as accessory spines. The walls of the pseudoproboscis possess a loose structure of parallel muscular fibres and glandular processes. The glandular syncytia, interpreted as modified tegumental perikarya, have basophilic cytoplasm and stain positively for protein and carbohydrate. They form cellular processes, which protrude to reach to the tegument. These results provide structural details characterising one of the rostellar types recognized in the order Cyclophyllidea, i.e. the davaineid rostellar apparatus.     

Notopentorchis cyathiformis (Frölich, 1791) n. comb. and N. iduncula (Spassky, 1946) (Cestoda: Paruterinidae) from Palaearctic swifts (Aves: Apodiformes), with a review of the genus Notopentorchis Burt, 1938

The type-specimens of Notopentorchis cyathiformis (Frölich, 1791) n. comb. from Apus apus are redescribed. N. iduncula (Spassky, 1946) is redescribed on the basis of specimens from A. apus and A. pallidus from the Kurish Spit (USSR), Great Britain and Morocco. A re-definition of the genus Notopentorchis Burt, 1938 is presented and it is considered to include all the known species of paruterinid cestodes from swifts (Apodiformes: Apodidae and Hemiprocnidae). The valid species recognised are N. collocaliae Burt, 1938 (type-species), N. javanica (Hübscher, 1937), N. micropus Singh, 1952, N. iduncula [Syn. N. isonciphora (Dollfus, 1958), syn. nov.], N. cyathiformis and N. bovieni (Hübscher, 1937). N. vesiculigera (Krabbe, 1882) is considered a species inquirenda, as are Sphaeruterina dikeniensis Mokhehle, 1951, Dilepis cypselina Neslobinsky, 1911 and Neoangularia micropusi Gupta & Sinha, 1985, which probably belong also to Notopentorchis. Notopentorchis hindia Johri, 1950 from Coraciiformes and N. kherai Duggal & Gupta, 1986 from Passeriformes are regarded as species incertae sedis.     

Distribution and Some Traits of Biology of Sculpins of Genus Triglops (Cottidae) in the Sea of Japan

Journal of Ichthyology - It was revealed that the southern border of the range of spectacled sculpin Triglops scepticus runs in the region of 37°23′ N. It has been confirmed that the...     

Structural basis of diversity and homodimerization specificity of zinc-finger-associated domains in Drosophila

In arthropods, zinc finger-associated domains (ZADs) are found at the N-termini of many DNA-binding proteins with tandem arrays of Cys2-His2 zinc fingers (ZAD-C2H2 proteins). ZAD-C2H2 proteins undergo fast evolutionary lineage-specific expansion and functional diversification. Here, we show that all ZADs from Drosophila melanogaster form homodimers, but only certain ZADs with high homology can also heterodimerize. CG2712, for example, is unable to heterodimerize with its paralog, the previously characterized insulator protein Zw5, with which it shares 46% homology. We obtained a crystal structure of CG2712 protein''s ZAD domain that, in spite of a low sequence homology, has similar spatial organization with the only known ZAD structure (from Grauzone protein). Steric clashes prevented the formation of heterodimers between Grauzone and CG2712 ZADs. Using detailed structural analysis, site-directed mutagenesis, and molecular dynamics simulations, we demonstrated that rapid evolutionary acquisition of interaction specificity was mediated by the more energy-favorable formation of homodimers in comparison to heterodimers, and that this specificity was achieved by multiple amino acid substitutions resulting in the formation or breaking of stabilizing interactions. We speculate that specific homodimerization of ZAD-C2H2 proteins is important for their architectural role in genome organization.     

The correlation of paraoxonase (PON1) activity with lipid and lipoprotein levels differs with vascular disease status

Paraoxonase (PON1) is an HDL-associated enzyme. Low PON1 activity predicts vascular disease status and is a more reliable predictor of vascular disease than are functional PON1 genotypes. There is evidence that the relationship of PON1 to vascular disease is, in part, due to its antioxidant activity. However, the physical relationship of PON1 with HDL and the existence of cholesterol pathway regulatory elements at the PON1 locus suggest a further relationship of PON1 with lipoproteins, which may contribute to its role in vascular disease. We investigated the relationship of PON1 activity and genotype to lipid-related traits in 91 Caucasian men with severe carotid artery disease and 184 without vascular disease who were not on lipid-lowering medications. Prior studies of PON1 relationship to lipids have not stratified by disease status.. We found that PON1 activity was correlated with HDL traits in controls and with LDL- and VLDL-related traits in cases. We hypothesize differences in the joint regulation of PON1 and lipoproteins in cases and controls.