Characterisation of two aphid picorna-like viruses

A new aphid virus, aphid lethal paralysis virus (ALPV), was isolated from laboratory-propagated Rhopalosiphum padi aphids co-infected with R. padi virus (RhPV). ALPV and RhPV were separated and ALPV was characterised in detail. Virions are isometric with a diameter of 26 nm, a sedimentation coefficient of 164 Sand a density in CsCl of 1.34 g/ml. Virions contain a 9.7 kb polyadenylated, singlestranded RNA and three major proteins with molecular weights of approximately 30 kilodaltons. By characterising RhPV further, two additional putative capsid proteins were found, an RNA poly(A) tract was detected and an RNA size of 10 kb was determined. A South African isolate of RhPV (RhPVoFs) was found to be serologically identical but physically distinct from a USA isolate. Complementary DNA was synthesized from RhPVOFS RNA and cloned into the plasmid vector, pBR322. This clone was used for the detettion of virus in aphids. ALPV and RhPV are serologically unrelated. ALPV is serologically distantly related to two insect picornaviruses, cricket paralysis virus (CrPV) and Drosophila C virus. No nucleic acid homology was detected between ALPV cDNA and CrPV by dot-blot hybridization. ALPV is serologically unrelated to seven other insect picornalike viruses. RhPV is serologically unrelated to any of the above mentioned viruses. ALPV and RhPV RNAs were efficiently translated in rabbit reticulocyte lysate into high molecular weight polypeptides, the sum of which exceeded the coding capacity of the genomes. Putative capsid precursor proteins of ALPV and RhPV were identified by immunoprecipitation. ALPV translation products were post-translationally cleaved as demonstrated in pulse-chase experiments and in experiments using a translation inhibitor. The efficiency of cleavage was concentration-dependent indicating the action of a protease. In parallel experiments with RhPV RNA, no evidence of post-translational cleavage was observed. In a survey of aphids collected in South Africa, ALPV and RhPV were detected in aphids from two major small-grain producing areas. Both viruses were found to naturally infect most of the cereal aphid species found in this country. ALPV and RhPV infections of R. padi resulted in a marked reduction in longevity and fecundity relative to uninfected aphids. Both viruses were found to be horizontally and vertically transmitted through aphid populations, and aphid host plants and aphid predators could be implicated in virus dissemination. ALPV and RhPV have many properties in common with each other as well as with insect and mammalian picornaviruses. Based on this data, it is proposed that ALPV and RhPV be classified into the picornavirus group (family Picornaviridae)

Human Immunodeficiency Virus? One of nature's greatest evolutionary machines

Transmission of an HIV-like virus from chimpanzees to humans approximately 80 years ago triggered the worldwide AIDS pandemic. Possessing very high mutation and recombination rates, the descendants of this ancestral virus have evolved greatly. Most of this evolution has been in response to selective pressures imposed by human immune responses and has not provided HIV with any significant new biological characteristics. The continuing diversification of HIV variants is a principal obstruction to controlling the virus with drugs and vaccines

From Observers to Participants: Joining the Scientific Community

In this essay, we have integrated the voices of our mentors and students to explore 45 years of undergraduate research experiences and their role in shaping our scientific community. In considering our collective experiences, we see undergraduate involvement in research as a rich source of community development, one that has both touched our lives and influenced our teaching

A novel candidate HIV vaccine vector based on the replication deficient Capripoxvirus, Lumpy skin disease virus (LSDV)

<p>Abstract</p> <p>Background</p> <p>The <it>Capripoxvirus</it>, Lumpy skin disease virus (LSDV) has a restricted host-range and is being investigated as a novel HIV-1 vaccine vector. LSDV does not complete its replication cycle in non-ruminant hosts.</p> <p>Methods</p> <p>The safety of LSDV was tested at doses of 10⁴and 10⁶plaque forming units in two strains of immunocompromised mice, namely RAG mice and CD4 T cell knockout mice. LSDV expressing HIV-1 subtype C Gag, reverse transcriptase (RT), Tat and Nef as a polyprotein (Grttn), (rLSDV-grttn), was constructed. The immunogenicity of rLSDV-grttn was tested in homologous prime-boost regimens as well as heterologous prime-boost regimes in combination with a DNA vaccine (pVRC-grttn) or modified vaccinia Ankara vaccine (rMVA-grttn) both expressing Grttn.</p> <p>Results</p> <p>Safety was demonstrated in two strains of immunocompromised mice.</p> <p>In the immunogenicity experiments mice developed high magnitudes of HIV-specific cells producing IFN-gamma and IL-2. A comparison of rLSDV-grttn and rMVA-grttn to boost a DNA vaccine (pVRC-grttn) indicated a DNA prime and rLSDV-grttn boost induced a 2 fold (p < 0.01) lower cumulative frequency of Gag- and RT-specific IFN-γ CD8 and CD4 cells than a boost with rMVA-grttn. However, the HIV-specific cells induced by the DNA vaccine prime rLSDV-grttn boost produced greater than 3 fold (p < 0.01) more IFN- gamma than the HIV-specific cells induced by the DNA vaccine prime rMVA-grttn boost. A boost of HIV-specific CD4 cells producing IL-2 was only achieved with the DNA vaccine prime and rLSDV-grttn boost. Heterologous prime-boost combinations of rLSDV-grttn and rMVA-grttn induced similar cumulative frequencies of IFN- gamma producing Gag- and RT-specific CD8 and CD4 cells. A significant difference (p < 0.01) between the regimens was the higher capacity (2.1 fold) of Gag-and RT-specific CD4 cells to produce IFN-γ with a rMVA-grttn prime - rLSDV-grttn boost. This regimen also induced a 1.5 fold higher (p < 0.05) frequency of Gag- and RT-specific CD4 cells producing IL-2.</p> <p>Conclusions</p> <p>LSDV was demonstrated to be non-pathogenic in immunocompromised mice. The rLSDV-grttn vaccine was immunogenic in mice particularly in prime-boost regimens. The data suggests that this novel vaccine may be useful for enhancing, in particular, HIV-specific CD4 IFN- gamma and IL-2 responses induced by a priming vaccine.</p

Relationship between levels of inflammatory cytokines in the genital tract and CD4+ cell counts in women with acute HIV-1 infection.

Inflammatory responses at mucosal surfaces after human immunodeficiency virus type 1 (HIV-1) transmission may influence disease outcome. We evaluated levels of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, IL-8, IL-10, and IL-12 in genital tract and plasma specimens from 44 women with acute HIV infection and 29 HIV-negative control women (13 of whom were women in the acute HIV infection cohort who had preinfection samples available for analysis). Women with acute HIV infection had significantly elevated levels of IL-6, IL-10, and IL-12 in genital tract specimens and elevated levels of IL-1beta, IL-8, and IL-10 in plasma specimens, compared with HIV-negative control women. Levels of IL-1beta, IL-6, and IL-8 in cervicovaginal specimens from women with acute HIV infection showed a significant inverse correlation with systemic CD4(+) cell counts, suggesting that mucosal inflammation is associated with low CD4(+) cell counts during acute HIV infection

First STEPS Phase II Initiative: Improving Developmental, Autism, and Lead Screening for Children

First STEPS (Strengthening Together Early Preventive Services) is a learning initiative supported by Maine\u27s CHIPRA quality demonstration grant to support measure-driven practice improvement in pediatric and family practices across the state on improving developmental, autism, and lead screening for children. This report, authored by research staff at the USM Muskie School, evaluates the impact of Phase II of Maine\u27s First STEPS initiative, which was implemented from May to December 2012 and included 12 practices serving more than 20,000 children on MaineCare (Maine\u27s Medicaid system). The authors assess changes in developmental, autism, and lead screening rates and evidence-based office processes in participating practices before and after the initiative, as well as related systems changes. They also summarize lessons learned in implementing changes in practices and challenges in using CHIPRA and IHOC developmental, autism, and lead screening measures at the practice-level to inform quality improvement

Use of spelling rules in school-aged children with Williams syndrome

Purpose: Researchers evaluating children’s spelling abilities usually score their spellings dichotomously - as correct or incorrect. This type of scoring is not as informative as procedures that take into consideration the plausibility of children’s spellings (Treiman et al., 2016). We examined the spelling abilities of children and adolescents with Williams syndrome (WS), a genetic disorder associated with intellectual disability, to determine if their spellings were based on English orthographic rules. Method: Sixty-six 9–17-year-olds with WS (M=13.50 years, SD=3.14) completed the Wechsler Individual Achievement Test-III (Wechsler, 2009) Spelling subtest. Items 6 to 16 were scored using the Ponto software (Kessler, 2017) to determine the extent to which children’s spelling differed from the correct spelling (the “letter distance ). Letter distance is calculated based on the transformations needed to change the child’s spelling to the correct spelling. Each insertion or deletion is scored 1, and each substitution is scored 1.4. If the word is spelled correctly, its letter distance is 0. Letter distance scores for the child’s spellings were compared to letter distance scores for random spellings, using the Monte Carlo method. Improvement scores were obtained by dividing a child’s sum of letter distances by the sum of random letter distances. Results: Children spelled a median of 10 (MAD=1) of 11 words correctly. Their mean improvement score was 0.89 (SD=0.14), which was significantly better than expected if their spelling had been random, p \u3c .001. Conclusion: Children and adolescents with WS have at least some knowledge of English orthographic spelling rules.https://ir.library.louisville.edu/uars/1054/thumbnail.jp

Virological features associated with the development of broadly neutralizing antibodies to HIV-1.

CAPRISA, 2015.Abstract available in pdf

Conserved positive selection signals in gp41 across multiple subtypes and difference in selection signals detectable in gp41 sequences sampled during acute and chronic HIV-1 subtype C infection

<p>Abstract</p> <p>Background</p> <p>The high diversity of HIV variants driving the global AIDS epidemic has caused many to doubt whether an effective vaccine against the virus is possible. However, by identifying the selective forces that are driving the ongoing diversification of HIV and characterising their genetic consequences, it may be possible to design vaccines that pre-empt some of the virus' more common evasion tactics. One component of such vaccines might be the envelope protein, gp41. Besides being targeted by both the humoral and cellular arms of the immune system this protein mediates fusion between viral and target cell membranes and is likely to be a primary determinant of HIV transmissibility.</p> <p>Results</p> <p>Using recombination aware analysis tools we compared site specific signals of selection in gp41 sequences from different HIV-1 M subtypes and circulating recombinant forms and identified twelve sites evolving under positive selection across multiple major HIV-1 lineages. To identify evidence of selection operating during transmission our analysis included two matched datasets sampled from patients with acute or chronic subtype C infections. We identified six gp41 sites apparently evolving under different selection pressures during acute and chronic HIV-1 infections. These sites mostly fell within functional gp41 domains, with one site located within the epitope recognised by the broadly neutralizing antibody, 4E10.</p> <p>Conclusion</p> <p>Whereas these six sites are potentially determinants of fitness and are therefore good candidate targets for subtype-C specific vaccines, the twelve sites evolving under diversifying selection across multiple subtypes might make good candidate targets for broadly protective vaccines.</p