Coassembly and complementation of Gag proteins from HIV-1 and HIV-2, two distinct human pathogens

Approximately one million people in the world are dually infected with both HIV-1 and HIV-2. To identify potential interactions between these two human pathogens, we examined whether HIV-1 and HIV-2 Gag proteins can coassemble and functionally complement each other. We generated HIV-1- and HIV-2-based vectors with mutations in Gag; compared with wild-type vectors, these mutants had drastically decreased viral titers. Coexpression of the mutant HIV-1 and HIV-2 Gag could generate infectious viruses; furthermore, heterologous complementation in certain combinations showed efficiency similar to homologous complementation. Additionally, we used bimolecular fluorescence complementation analysis to directly demonstrate that HIV-1 and HIV-2 Gag can interact and coassemble. Taken together, our results indicate that HIV-1 and HIV-2 Gag polyproteins can coassemble and functionally complement each other during virus replication; to our knowledge, this is the first demonstration of its kind. These studies have important implications for AIDS treatment and the evolution of primate lentiviruses.     

Luciferase-based transgenic recombination assay is more sensitive than beta-glucoronidase-based

Study of the DNA repair and genome stability in plants is directly dependent on the availability of an easy, inexpensive, and reliable assay. Marker gene-based homologous recombination (HR) assays were introduced more than a decade ago and have been intensively used ever since. Here, we compared several transgenic Arabidopsis and tobacco lines that carried in their genome the luciferase (LUC) or the beta-glucoronidase (uidA or GUS) substrates for HR. The average recombination frequency detected with the luciferase transgene was nearly 9.0-fold higher in Arabidopsis and 12.4-fold higher in tobacco plants. Importantly, both transgenes were under the control of 35S promoter and had similar expression levels throughout the plants. Irradiation with UVC increased the HR frequency similarly in both transgenes. The actual difference in the frequency of HR in Arabidopsis and tobacco possibly results from differing sensitivity to detection of transgene activity. Thus, we could suggest that luciferase recombination assay, due to its higher sensitivity, should be the assay of choice when plant genome stability is studied.     

The genus Biuterina Fuhrmann, 1902 (Cestoda,Paruterinidae) in the Old World: redescriptions of four species from Afrotropical Passeriformes

Four species of Biuterina Fuhrmann, 1902 (Cestoda, Cyclophyllidea, Paruterinidae), originally described from Afrotropical passeriform birds, are redescribed and figured on the basis of their type-specimens. These are B. pentamyzos (Mettrick, 1960) from Prionops plumata (Laniidae) in Zimbabwe, B. quelea (Mettrick, 1963) from Quelea quelea (Ploceidae) in Zimbabwe, B. ugandae Baylis, 1919 from Chalcomitra senegalensis (Nectariniidae) in Uganda and B. zambiensis (Mettrick, 1960) from Campephaga flava (Campephagidae) in Zimbabwe. The rostellum of B. quelea is a spherical structure filled with strongly-developed glandular tissue and possessing a weak musculature. The remaining three species have a sucker-like rostellar apparatus with moderately developed glandular tissue in the rostellum and around it. It is considered that the glandular elements are an inherent part of the rostellar apparatus of the paruterinids. An armament consisting of fine, punctiform, spine-like structures arranged in transverse rows on the inner surface of suckers is observed in B. pentamyzos. This is the first record of sucker armature in the Paruterinidae.     

Cellular targets of functional and dysfunctional mutants of tobacco mosaic virus movement protein fused to green fluorescent protein

Intercellular transport of tobacco mosaic virus (TMV) RNA involves the accumulation of virus-encoded movement protein (MP) in plasmodesmata (Pd), in endoplasmic reticulum (ER)-derived inclusion bodies, and on microtubules. The functional significance of these interactions in viral RNA (vRNA) movement was tested in planta and in protoplasts with TMV derivatives expressing N- and C-terminal deletion mutants of MP fused to the green fluorescent protein. Deletion of 55 amino acids from the C terminus of MP did not interfere with the vRNA transport function of MP:GFP but abolished its accumulation in inclusion bodies, indicating that accumulation of MP at these ER-derived sites is not a requirement for function in vRNA intercellular movement. Deletion of 66 amino acids from the C terminus of MP inactivated the protein, and viral infection occurred only upon complementation in plants transgenic for MP. The functional deficiency of the mutant protein correlated with its inability to associate with microtubules and, independently, with its absence from Pd at the leading edge of infection. Inactivation of MP by N-terminal deletions was correlated with the inability of the protein to target Pd throughout the infection site, whereas its associations with microtubules and inclusion bodies were unaffected. The observations support a role of MP-interacting microtubules in TMV RNA movement and indicate that MP targets microtubules and Pd by independent mechanisms. Moreover, accumulation of MP in Pd late in infection is insufficient to support viral movement, confirming that intercellular transport of vRNA relies on the presence of MP in Pd at the leading edge of infection.     

A molecular phylogeny of Bopyroidea and Cryptoniscoidea (Crustacea: Isopoda)

Epicaridean isopods are parasitic on other crustaceans. They represent a diverse group of highly derived taxa in two superfamilies and 10 families. Little work has been done on the phylogeny of these parasites because of the difficulty in defining homologous characters for adults above the genus level. The females exhibit morphological reduction of characters and the males have few distinguishing characters. Moreover, epicarideans have only rarely been included in past studies of isopod phylogeny. Our objective was to derive a phylogeny of epicaridean taxa based on 18S rDNA, then use that phylogeny to examine the relationships of the bopyrid subfamilies, bopyroid families and epicarideans to cymothoid isopods. We tested the monophyly of the Epicaridea, evaluated hypotheses on relationships among epicaridean families and subfamilies, examined the evolution of the abdominal mode of infestation on caridean, gebiidean, axiidean and anomuran hosts and examined coevolution between epicarideans and their crustacean hosts. The molecular phylogeny indicated that Epicaridea were monophyletic with respect to Cymothooidea. Bopyroidea formed a monophyletic group without Dajidae and Entophilinae (now as Entophilidae). Both latter taxa grouped with Cryptoniscoidea, and this group was the sister taxon to the redefined Bopyroidea in all trees. The bopyrid subfamily Ioninae is the sister taxon to the other bopyrid subfamilies (except Entophilidae). Ioninae was elevated to family status but found not to be monophyletic; a new subfamily, Keponinae, was erected for all genera formerly placed in Ioninae except the type genus. The abdominal mode of parasitism appears to have evolved independently among the subfamilies. Coevolution between host and parasite phylogenies showed extensive incongruence, indicating frequent host-switching as a general pattern in Epicaridea.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:30ECFB13-2795-494E-AABE-6B5F84A57A67     

Variability of the Mitochondrial Genome and Development of the Primary Progressing form of Multiple Sclerosis

Molecular Biology - Recently, it has been shown that dysfunction of mitochondria is an important component of the molecular mechanisms of the development of many neurodegenerative diseases. These...     

Pharmacogenomics of multiple sclerosis: Association of immune response gene polymorphisms with copaxone treatment efficacy

A complex association analysis of copaxone (glatiramer acetate) immunotherapy efficacy with allelic polymorphism of the number of immune response genes, including the genes for interferon β (IFNB1), transforming growth factor β1 (TGFB1), interferon γ (IFNG), tumor necrosis factor (TNF), interferon α/β receptor 1 (IFNAR1), CC chemokine receptor 5 (CCR5), interleukin 7 receptor subunit α (IL7RA), cytotoxic T-lymphocyte antigen 4 (CTLA4), and HLA class II histocompatibility antigen β chain (DRB1), was performed using the APSampler algorithm for 285 multiple sclerosis patients of Russian ethnicity. The results demonstrate that the polymorphic variants of CCR5, DRB1, IFNG, TGFB1, IFNAR1, IL7RA, and, possibly, TNF and CTLA4 contribute to the copaxone treatment response. Single alleles of CCR5 and DRB1 genes were reliably associated with treatment efficacy. Allelic variants of the other genes exerted a weaker, though still reliable, effect on the copaxone treatment response, but as part of bi- and triallelic combinations only. The study may provide a basis for a prognostic test allowing an individual choice of immune-modulating treatment for a patient with multiple sclerosis.     

The molecular bases of plant resistance and defense responses to aphid feeding: current status

Plant genes participating in the recognition of aphid herbivory in concert with plant genes involved in defense against herbivores mediate plant resistance to aphids. Several such genes involved in plant disease and nematode resistance have been characterized in detail, but their existence has only recently begun to be determined for arthropod resistance. Hundreds of different genes are typically involved and the disruption of plant cell wall tissues during aphid feeding has been shown to induce defense responses in Arabidopsis, Triticum, Sorghum, and Nicotiana species. Mi‐1.2, a tomato gene for resistance to the potato aphid, Macrosiphum euphorbiae (Thomas), is a member of the nucleotide‐binding site and leucine‐rich region Class II family of disease, nematode, and arthropod resistance genes. Recent studies into the differential expression of Pto‐ and Pti1‐like kinase genes in wheat plants resistant to the Russian wheat aphid, Diuraphis noxia (Mordvilko), provide evidence of the involvement of the Pto class of resistance genes in arthropod resistance. An analysis of available data suggests that aphid feeding may trigger multiple signaling pathways in plants. Early signaling includes gene‐for‐gene recognition and defense signaling in aphid‐resistant plants, and recognition of aphid‐inflicted cell damage in both resistant and susceptible plants. Furthermore, signaling is mediated by several compounds, including jasmonic acid, salicylic acid, ethylene, abscisic acid, giberellic acid, nitric oxide, and auxin. These signals lead to the development of direct chemical defenses against aphids and general stress‐related responses that are well characterized for a number of abiotic and biotic stresses. In spite of major plant taxonomic differences, similarities exist in the types of plant genes expressed in response to feeding by different species of aphids. However, numerous differences in plant signaling and defense responses unique to specific aphid–plant interactions have been identified and warrant further investigation.