scholarly journals Life Cycle and Transmission of Cyclospora cayetanensis: Knowns and Unknowns

2022 ◽  
Vol 10 (1) ◽  
pp. 118
Author(s):  
Jitender P. Dubey ◽  
Asis Khan ◽  
Benjamin M. Rosenthal
Keyword(s):  
Life Cycle ◽  
Epithelial Cells ◽  
Histological Examination ◽  
Intestinal Epithelium ◽  
Endogenous Development ◽  
Cyclospora Cayetanensis ◽  
Histological Sections ◽  
Biopsy Specimens ◽  
Eimeria Spp ◽  
Sexual Stages

Although infections with Cyclospora cayetanensis are prevalent worldwide, many aspects of this parasite’s life cycle and transmission remain unknown. Humans are the only known hosts of this parasite. Existing information on its endogenous development has been derived from histological examination of only a few biopsy specimens. Its asexual and sexual stages occur in biliary-intestinal epithelium. In histological sections, its stages are less than 10 μm, making definitive identification difficult. Asexual (schizonts) and sexual (gamonts) are located in epithelial cells. Male microgamonts have two flagella; female macrogametes contain wall-forming bodies. Oocysts are excreted in feces unsporulated. Sporulation occurs in the environment, but there are many unanswered questions concerning dissemination and survival of C. cayetanensis oocysts. Biologically and phylogenetically, C. cayetanensis closely resembles Eimeria spp. that parastize chickens; among them, E. acervulina most closely resembles C. cayetanensis in size. Here, we review known and unknown aspects of its life cycle and transmission and discuss the appropriateness of surrogates best capable of hastening progress in understanding its biology and developing mitigating strategies.

Eimeria mitis: a comparison of the endogenous developmental stages of a line selected for early maturation and the parent strain

Parasitology ◽  
1984 ◽  
Vol 88 (1) ◽  
pp. 37-44 ◽  
Author(s):  
V. McDonald ◽  
M. W. Shirley
Keyword(s):  
Life Cycle ◽  
Epithelial Cells ◽  
Parent Strain ◽  
First Generation ◽  
Developmental Stages ◽  
Reproductive Potential ◽  
Life Cycles ◽  
Endogenous Development ◽  
Early Maturation ◽  
Precocious Line

SUMMARYThe endogenous development of the Houghton (H) strain of Eimeria mitis (= mivati) was compared with the life-cycle of a precocious (HP) line derived from the H strain. In both parasites 4 generations of schizonts which developed in epithelial cells were observed: the 1st and 2nd were found in the crypts and the 3rd and 4th in the villi. Gametocytes and zygotes occupied epithelial cells at the tips of the villi. The onset of gametogony normally coincided with the maturation of 4th-generation schizonts. The infection was confined initially to an area of the gut extending from the jejunum to the ileo-caecal junction but 3rd-generation merozoites and subsequent stages were also found in the caeca and rectum. The life-cycle of the precocious line was shorter than that of the parent strain. Gametocytes appeared to develop from 3rd-generation as well as from 4th-generation merozoites. Also, sporozoites of the precocious line transformed to trophozoites before those of the parent strain. First-generation schizonts of the HP line tended to be smaller and to contain fewer merozoites than those of the H strain. The differences between the life-cycles of the two parasites account for the lower reproductive potential of the precocious line.

Eimeria hermani Farr, 1953 of the Canada goose, Branta canadensis: endogenous development, including intranuclear schizogony, in the domestic goose (Anser anser domesticus)

1990 ◽  
Vol 68 (11) ◽  
pp. 2424-2428 ◽  
Author(s):  
R. C. Skene ◽  
M. A. Fernando
Keyword(s):  
Epithelial Cells ◽  
Parasitophorous Vacuole ◽  
Endogenous Development ◽  
Canada Goose ◽  
Anser Anser ◽  
Coccidian Parasites ◽  
Two Generations ◽  
Sexual Stages ◽  
Basal Position ◽  
Endogenous Stages

All endogenous stages of Eimeria hermani were found throughout the small intestine of experimentally infected domestic goslings. At least two generations of schizogony were seen to occur prior to gamogony, and mature schizonts were seen from 36 to 84 h postinfection. Developing gamonts were seen between 96 and 120 h postinfection and oocysts were seen in histological sections by 132 h. All schizogonic stages occurred within the nuclei of epithelial cells whereas the sexual stages were found within the cytoplasm of epithelial cells. Infected nuclei appeared close to the brush border of epithelial cells, in contrast to the basal position occupied by uninfected nuclei. The schizonts and the resulting merozoites lay within a parasitophorous vacuole bounded by a vacuolar membrane. In infected nuclei a dissociation of the granular and fibrillar portions of the nucleolus was apparent and the heterochromatin was concentrated near the nuclear membrane. The ultrastructure of the merozoites is described and the intranuclear development of the asexual stages of E. hermani is discussed in relation to previously described intranuclear coccidian parasites.

Life-cycle of Isospora ohioensis in dogs

Parasitology ◽  
1978 ◽  
Vol 77 (1) ◽  
pp. 1-11 ◽  
Author(s):  
J. P. Dubey
Keyword(s):  
Life Cycle ◽  
Epithelial Cells ◽  
Lymph Nodes ◽  
Parasitophorous Vacuole ◽  
Post Inoculation ◽  
Type I ◽  
Mesenteric Lymph Nodes ◽  
Mesenteric Lymph ◽  
Asexual Multiplication ◽  
Sexual Stages

SummaryThe life-cycle of Isospora ohioensis in dogs is described. Eight dogs were killed 6, 16, 24, 48, 72, 96, 114 and 120 h after feeding 106I. ohioensis sporocysts to each. First divisional stages occurred in the jejunum at 48 h post-inoculation (p.i.). At 48 h, zoites occurred in pairs in parasitophorous vacuoles of surface epithelial cells of the jejunum. The parasitophorous vacuoles were 7–9 × 6 μm and the zoites were 7–9 × 2·5 μm in sections. At 72 h, uninucleated zoites, multinucleated zoites and meronts containing fully formed merozoites occurred in surface epithelial cells of the jejunum. At 96, 114 and 120 h asexual multiplication occurred throughout the small and large intestine, mostly in the ileum. The number of asexual generations was not determined. At least 2 structurally distinct meronts were identified at 96–120 h p.i. Type I meronts contained larger merozoites (11 × 3 μm) than those (7·5 × 1·5 μm) in Type II meronts. Meronts were merozoite-shaped and contained up to 8 nuclei. Uninucleated, binucleated and multinucleated zoites occurred within the same parasitophorous vacuole. Gamonts occurred in surface epithelial cells of the small intestine, caecum and colon, but predominantly in the ileum, 96–120 h p.i. Macrogamonts were 13–17 × 11–12 (14·5 × 12·8) μm in sections and 21–26 × 17–25 (21·7 × 17·6) μm in smears. Microgamonts were 13–17 × 8–15 (15·3 × 11·4) μm in sections and 24–30 × 15–24 (27 × 19) μm in smears and contained up to 50 microgametes. The cycle was also studied in 6 dogs killed 6, 12, 24, 48, 96 and 120 h after feeding tissues of laboratory mice that had been infected with I. ohioensis oocysts 17 days earlier. Stages were not seen in the dogs killed at 6 and 12 h p.i. Asexual and sexual stages were structurally similar in size and location to the oocyst-induced cycle but their development was faster by 24 h in the mouse-induced cycle. Extra-intestinal stages were not found in sections of mesenteric lymph nodes, spleen, lung, liver, heart, skeletal muscle and brain. However, biological evidence indicated that I. ohioensis invaded the spleens and mesenteric lymph nodes of dogs fed oocysts.

Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells

1971 ◽  
Vol 29 ◽  
pp. 572-573
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Liver Biopsy ◽  
Alcoholic Hepatitis ◽  
Ultrastructural Changes ◽  
Main Mass ◽  
Biliary Epithelial Cells ◽  
Biopsy Specimens ◽  
Alcoholic Hyalin

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.

scholarly journals A Micro-engineered Human Colon Intestine-Chip Platform to Study Leaky Barrier

2020 ◽  
Author(s):  
Athanasia Apostolou ◽  
Rohit A. Panchakshari ◽  
Antara Banerjee ◽  
Dimitris V. Manatakis ◽  
Maria D. Paraskevopoulou ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Intestinal Epithelium ◽  
Unmet Need ◽  
Intestinal Barrier ◽  
Human Colon ◽  
Epithelial Barrier ◽  
Host Immune System ◽  
Intestinal Epithelial ◽  
Barrier Disruption ◽  
Interleukin 22

ABSTRACTThe intestinal epithelial barrier supports the symbiotic relationship between the microbiota colonizing the intestinal epithelium and the host immune system to maintain homeostasis. Leaky barrier is increasingly recognized as part of the pathogenesis of a number of chronic conditions in addition to inflammatory and infectious diseases. As our understanding on the regulation of the barrier remains limited, effective therapeutic targeting for the compromised barrier is still an unmet need. Here we combined advancements on the organoids and Organ-on-Chip technologies to establish a micro-engineered Colon Intestine-Chip for studying development and regulation of the human intestinal barrier. Our data demonstrate the significance of the endothelium in co-culture with the epithelial cells within a tissue-relevant microenvironment for the establishment of a tight epithelial barrier of polarized cells. Pathway analysis of the RNA sequencing (RNA-Seq), revealed significant upregulation of mechanisms relevant to the maturation of the intestinal epithelium in organoid-derived epithelial cells in co-culture with endothelium as compared to organoids maintained in suspension. We provide evidence that the Colon Intestine-Chip platform responds to interferon gamma (IFNγ), a prototype cytokine utilized to model inflammation-induced barrier disruption, by induction of apoptosis and reorganization of the apical junctional complexes as shown with other systems. We also describe the mechanism of action of interleukin 22 (IL-22) on mature, organoid-derived intestinal epithelial cells that is consistent with barrier disruption. Overall we propose the Colon Intestine-Chip as a promising human organoid-derived platform to decipher mechanisms driving the development of leaky gut in patients and enable their translation for this unmet medical need.

Diagnostic strategies for the histological examination of muscle biopsy specimens for the assessment of vasculitis in rheumatoid arthritis

2000 ◽  
Vol 19 (24) ◽  
pp. 3433-3447 ◽  
Author(s):  
Aeilko H. Zwinderman ◽  
Alexandre E. Voskuyl ◽  
David D. Schelhaas ◽  
Sjoerd G. van Duinen ◽  
Johanna M. van der Bas ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Histological Examination ◽  
Muscle Biopsy ◽  
Diagnostic Strategies ◽  
Biopsy Specimens

scholarly journals The Interferon Type I/III Response to Respiratory Syncytial Virus Infection in Airway Epithelial Cells Can Be Attenuated or Amplified by Antiviral Treatment

2015 ◽  
Vol 90 (4) ◽  
pp. 1705-1717 ◽  
Author(s):  
K. M. McCutcheon ◽  
R. Jordan ◽  
M. E. Mawhorter ◽  
S. L. Noton ◽  
J. G. Powers ◽  
...  
Keyword(s):  
Life Cycle ◽  
Respiratory Syncytial Virus ◽  
Epithelial Cells ◽  
Viral Replication ◽  
Airway Epithelial Cells ◽  
Therapeutic Interventions ◽  
Airway Epithelial ◽  
Antiviral Activities ◽  
Syncytial Virus ◽  
Interferon Responses

ABSTRACTHuman respiratory syncytial virus (RSV) is a single-stranded RNA virus that causes acute, and occasionally fatal, lower respiratory illness in young infants, the elderly, and immunocompromised patients. Therapeutic interventions able to cut short viral replication and quickly return the airways to normal function are needed. An understanding of antiviral activities and their effects on host defense mechanisms is important for the design of safe and effective therapy. We targeted functionally and temporally distinct steps within the viral life cycle using small-molecule RSV inhibitors and studied their antiviral activities and their effects on innate interferon responses of airway epithelial cellsin vitro. Antivirals acting upstream of RSV polymerase activity (i.e., compounds targeting the fusion protein or the nucleoprotein) reduced viral load immediately postinfection and partially attenuated interferon responses. In contrast, antivirals directed to the RSV polymerase demonstrated activity throughout the viral replication cycle and specifically modulated the RIG-I/mitochondrial antiviral signaling protein (MAVS)/TBK1/IRF3/interferon-stimulated gene (ISG) axis, causing either an upregulation or a downregulation of interferon responses, depending on the mechanism of polymerase inhibition. Notably, polymerase inhibition leading to the accumulation of abortive RNA products correlated with the amplification of interferon-stimulated genes to up to 10 times above normal infection levels. Understanding how antiviral activities and their modulation of innate immunity may affect recovery from RSV infection will help guide the development of safe and effective therapies.IMPORTANCERSV circulates seasonally, causing acute lower respiratory disease. Therapeutic interventions with efficacy throughout the viral replication cycle, rapid viral clearance, and prevention of potentially harmful inflammatory responses are desirable. Compounds targeting the RSV polymerase inhibited virus replication late in the viral life cycle and, depending on the functional domain targeted, either attenuated or amplified RIG-I and downstream interferon pathways in infected cells. These data will help guide the development of safe and effective therapies by providing new molecular evidence that the mechanism of inhibition by an antiviral compound can directly impact innate antiviral immune responses in the airway epithelium.

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