Browsing by Author "Song, M"

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    A novel chloroplast gene reported for flagellate plants.
    (American journal of botany, 2018-01) Song, M; Kuo, L; Huiet, L; Pryer, KM; Rothfels, CJ; Li, F
    PREMISE OF THE STUDY:Gene space in plant plastid genomes is well characterized and annotated, yet we discovered an unrecognized open reading frame (ORF) in the fern lineage that is conserved across flagellate plants. METHODS:We initially detected a putative uncharacterized ORF by the existence of a highly conserved region between rps16 and matK in a series of matK alignments of leptosporangiate ferns. We mined available plastid genomes for this ORF, which we now refer to as ycf94, to infer evolutionary selection pressures and assist in functional prediction. To further examine the transcription of ycf94, we assembled the plastid genome and sequenced the transcriptome of the leptosporangiate fern Adiantum shastense Huiet & A.R. Sm. KEY RESULTS:The ycf94 predicted protein has a distinct transmembrane domain but with no sequence homology to other proteins with known function. The nonsynonymous/synonymous substitution rate ratio of ycf94 is on par with other fern plastid protein-encoding genes, and additional homologs can be found in a few lycophyte, moss, hornwort, and liverwort plastid genomes. Homologs of ycf94 were not found in seed plants. In addition, we report a high level of RNA editing for ycf94 transcripts-a hallmark of protein-coding genes in fern plastomes. CONCLUSIONS:The degree of sequence conservation, together with the presence of a distinct transmembrane domain and RNA-editing sites, suggests that ycf94 is a protein-coding gene of functional significance in ferns and, potentially, bryophytes and lycophytes. However, the origin and exact function of this gene require further investigation.
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    Enhanced de novo alloantibody and antibody-mediated injury in rhesus macaques.
    (Am J Transplant, 2012-09) Page, EK; Page, AJ; Kwun, J; Gibby, AC; Leopardi, F; Jenkins, JB; Strobert, EA; Song, M; Hennigar, RA; Iwakoshi, N; Knechtle, SJ
    Chronic allograft rejection is a major impediment to long-term transplant success. Humoral immune responses to alloantigens are a growing clinical problem in transplantation, with mounting evidence associating alloantibodies with the development of chronic rejection. Nearly a third of transplant recipients develop de novo antibodies, for which no established therapies are effective at preventing or eliminating, highlighting the need for a nonhuman primate model of antibody-mediated rejection. In this report, we demonstrate that depletion using anti-CD3 immunotoxin (IT) combined with maintenance immunosuppression that included tacrolimus with or without alefacept reliably prolonged renal allograft survival in rhesus monkeys. In these animals, a preferential skewing toward CD4 repopulation and proliferation was observed, particularly with the addition of alefacept. Furthermore, alefacept-treated animals demonstrated increased alloantibody production (100%) and morphologic features of antibody-mediated injury. In vitro, alefacept was found to enhance CD4 effector memory T cell proliferation. In conclusion, alefacept administration after depletion and with tacrolimus promotes a CD4+memory T cell and alloantibody response, with morphologic changes reflecting antibody-mediated allograft injury. Early and consistent de novo alloantibody production with associated histological changes makes this nonhuman primate model an attractive candidate for evaluating targeted therapeutics.
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    Re-Membering 'Race': On Gender, 'Mixed Race' and Family in the English-African Diaspora
    (Rethinking mixed race, 2001-05-20) Ifekwunigwe, JO