5 results on '"C. Racicot"'
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2. High genetic diversities between isolates of the fish parasite Cryptocaryon irritans (Ciliophora) suggest multiple cryptic species
- Author
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Alycia C. Racicot, Emily J. Foley, Kosuke Zenke, Yen-Ling Song, Hongshu Chi, Hui Gong, Hsin-Yun Lin, Katherine E. Guzzetta, Tomoyoshi Yoshinaga, Che-Huang Tung, Chao-Yin Cheng, Patricia Taik, Hilary M. Gray, and Wei-Jen Chang
- Subjects
0301 basic medicine ,China ,Species complex ,Genetic Speciation ,Taiwan ,Aquaculture ,Subspecies ,03 medical and health sciences ,Japan ,Phylogenetics ,Genetics ,Animals ,Parasite hosting ,Molecular Biology ,Phylogeny ,Ecology, Evolution, Behavior and Systematics ,Hymenostomatida ,Ichthyophthirius multifiliis ,biology ,Cryptocaryon ,Fishes ,Genetic Variation ,Reproductive isolation ,biology.organism_classification ,030104 developmental biology ,GenBank - Abstract
The ciliate protozoan Cryptocaryon irritans parasitizes marine fish and causes lethal white spot disease. Sporadic infections as well as large-scale outbreaks have been reported globally and the parasite's broad host range poses particular threat to the aquaculture and ornamental fish markets. In order to better understand C. irritans' population structure, we sequenced and compared mitochondrial cox-1, SSU rRNA, and ITS-1 sequences from 8 new isolates of C. irritans collected in China, Japan, and Taiwan. We detected two SSU rRNA haplotypes, which differ at three positions, separating the isolates into two main groups (I and II). Cox-1 sequences also support the division into two groups, and the cox-1 divergence between these two groups is unexpectedly high (9.28% for 1582 nucleotide positions). The divergence is much greater than that detected in Ichthyophthirius multifiliis, the ciliate protozoan causing freshwater white spot disease in fish, where intraspecies divergence on cox-1 sequence is only 1.95%. ITS-1 sequences derived from these eight isolates and from all other C. irritans isolates (deposited in the GenBank) not only support the two groups, but further suggest the presence of a third group with even greater sequence divergence. Finally, a small Ka/Ks ratio estimated from cox-1 sequences suggests that this gene in C. irritans remains under strong purifying selection. Taken together, the C. irritans species may consists of many subspecies and/or syngens. Further work is needed to determine if there is reproductive isolation between the groups we have defined.
- Published
- 2017
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3. Hypocalcemia Induced during Major and Minor Abdominal Surgery in Humans
- Author
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G. Legare, M. Dagenais, Pierre D’Amour, C. Racicot, Réal Lapointe, Raymond Lepage, and Jean-Hugues Brossard
- Subjects
medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Clinical Biochemistry ,Serum albumin ,chemistry.chemical_element ,Calcium ,Biochemistry ,Anesthesia Procedure ,Endocrinology ,Internal medicine ,Medicine ,Colectomy ,Calcium metabolism ,biology ,business.industry ,Biochemistry (medical) ,Albumin ,Surgery ,chemistry ,Anesthesia ,biology.protein ,Hepatectomy ,business ,Abdominal surgery - Abstract
Hypocalcemia has only been rarely reported during surgical procedures not involving massive blood transfusions. The frequent observation in our hospital of a low serum ionized calcium level during surgery in nonacutely ill patients prompted us to investigate the calcium-PTH axis in three groups of subjects undergoing major (hepatectomy; n = 10), moderately severe, or minor surgery under general anesthesia (colectomy; n = 7, herniorrhaphy; n = 9) compared to that in one group of minor surgery cases under epidural anesthesia (herniorrhaphy; n = 15). Serum samples were obtained before anesthesia, after anesthesia but before surgery, and 40 and 120 min after the beginning of surgery in all groups of patients and for up to 3 days in major and moderately severe cases. Significant falls (P < 0.01), always proportional to the severity of the surgical/anesthesia procedure, were observed for ionized calcium (6-20%), total calcium (8-19%), and albumin (8-23%) accompanied by increases in intact PTH (105-635%). The decrease in ionized and total calcium correlated with a decrease in albumin (P < 0.001). Phosphorus, pH, and magnesium levels remained within the normal range. Adjustment of ionized calcium for variation in albumin revealed that 50-100% of the variation in ionized calcium could be attributed to a fall in albumin resulting from fluid administration to patients before admission to the surgery ward and between the onset of anesthesia and the end of surgery (1.2-5.6 L). Albumin- and pH-independent residual ionized calcium decreases of 12.2% in the hepatectomy group, 4.6% in the group of moderately severe and minor cases under general anesthesia, and 3.7% in the control group reflected the severity of the surgical/anesthesia procedure.
- Published
- 1999
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- View/download PDF
4. Arabinosylation of recombinant human immunoglobulin-based protein therapeutics.
- Author
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Hossler P, Chumsae C, Racicot C, Ouellette D, Ibraghimov A, Serna D, Mora A, McDermott S, Labkovsky B, Scesney S, Grinnell C, Preston G, Bose S, and Carrillo R
- Subjects
- Animals, Antibodies, Monoclonal chemistry, Antibodies, Monoclonal genetics, Antibody-Dependent Cell Cytotoxicity, CHO Cells, Cricetulus, Glycosylation drug effects, Humans, Immunoglobulin G chemistry, Immunoglobulin G genetics, Recombinant Proteins biosynthesis, Recombinant Proteins chemistry, Recombinant Proteins genetics, Antibodies, Monoclonal biosynthesis, Arabinose pharmacology, Immunoglobulin G blood
- Abstract
Protein glycosylation is arguably the paramount post-translational modification on recombinant glycoproteins, and highly cited in the literature for affecting the physiochemical properties and the efficacy of recombinant glycoprotein therapeutics. Glycosylation of human immunoglobulins follows a reasonably well-understood metabolic pathway, which gives rise to a diverse range of asparagine-linked (N-linked), or serine/threonine-linked (O-linked) glycans. In N-linked glycans, fucose levels have been shown to have an inverse relationship with the degree of antibody-dependent cell-mediated cytotoxicity, and high mannose levels have been implicated in potentially increasing immunogenicity and contributing to less favorable pharmacokinetic profiles. Here, we demonstrate a novel approach to potentially reduce the presence of high-mannose species in recombinant human immunoglobulin preparations, as well as facilitate an approximate 100% replacement of fucosylation with arabinosylation in Chinese hamster ovary cell culture through media supplementation with D-arabinose, an uncommonly used mammalian cell culture sugar substrate. The replacement of fucose with arabinose was very effective and practical to implement, since no cell line engineering or cellular adaptation strategies were required. Arabinosylated recombinant IgGs and the accompanying reduction in high mannose glycans, facilitated a reduction in dendritic cell uptake, increased FcγRIIIa signaling, and significantly increased the levels of ADCC. These aforementioned effects were without any adverse changes to various structural or functional attributes of multiple recombinant human antibodies and a bispecific DVD-Ig. Protein arabinosylation represents an expansion of the N-glycan code in mammalian expressed glycoproteins.
- Published
- 2017
- Full Text
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5. Macrophage-mediated responses to Candida albicans in mice expressing the human immunodeficiency virus type 1 transgene.
- Author
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Goupil M, Trudelle EB, Dugas V, Racicot-Bergeron C, Aumont F, Sénéchal S, Hanna Z, Jolicoeur P, and de Repentigny L
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- Animals, CD4-Positive T-Lymphocytes physiology, Candidiasis, Oral immunology, Cell Polarity, Female, Gastric Mucosa microbiology, Hydrogen Peroxide metabolism, Macrophages metabolism, Male, Mice, Mice, Inbred C3H, Mice, Transgenic, Mouth Mucosa microbiology, Nitric Oxide Synthase Type II physiology, Phagocytosis, Transgenes, Tumor Necrosis Factor-alpha biosynthesis, Acquired Immunodeficiency Syndrome immunology, Candida albicans immunology, HIV-1 genetics, Macrophages immunology
- Abstract
The critical impairments of innate and adaptive immunity that cause susceptibility to mucosal candidiasis in human immunodeficiency virus (HIV) infection have not been fully determined. We therefore conducted an analysis of macrophage-mediated responses to Candida albicans in transgenic (Tg) mice expressing Nef, Env, and Rev of HIV type 1 (HIV-1) in CD4(+) T cells, dendritic cells, and macrophages and developing an AIDS-like disease (CD4C/HIV(MutA) Tg mice). Macrophages were successfully recruited to the oral and gastric mucosae of these Tg mice in response to chronic carriage of C. albicans and displayed polarization toward an alternatively activated phenotype. Functionally, peritoneal macrophages from uninfected Tg mice exhibited increased phagocytosis of C. albicans and enhanced production of interleukin 6 and monocyte chemoattractant protein 1, demonstrating that the HIV-1 transgene independently activates selected macrophage functions. Production of H(2)O(2) by macrophages from Tg mice primed with gamma interferon and treated with phorbol 12-myristate 13-acetate or C. albicans was moderately reduced, but expression of the HIV-1 transgene did not alter production of nitric oxide or reduce killing of C. albicans. A knockout of the inducible nitric oxide synthase (NOS2) gene in these Tg mice did not augment oral or gastrointestinal burdens during chronic carriage of C. albicans or cause systemic dissemination, likely due to a redundancy provided by partially preserved production of H(2)O(2) and oxygen-independent candidacidal mechanisms. Thus, the macrophage response to C. albicans is largely preserved in these Tg mice, and no functional macrophage defect appears to primarily determine the susceptibility to mucosal candidiasis.
- Published
- 2009
- Full Text
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