Electron microscopic studies of saprobic and parasitic forms of<i>Coccidioides immitis</i>

Sun, Steven; Sekhon, Sant S.; Huppert, M.

doi:10.1080/00362177985380391

Cited by 37 publications

(12 citation statements)

References 32 publications

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“…Humans and a variety of mammalian species, including dogs, cats, horses, South American camelids, and marine mammals [3–7], can be infected when aerosolized arthroconidia (asexual spores) are inhaled. Although the precise ecological niche of Coccidioides remains unknown, it is widely accepted that the fungus grows in soil as hyphae and produces infective arthroconidia that become airborne upon soil disturbance [8–10]. …”

Section: Introductionmentioning

confidence: 99%

Development of an enzyme immunoassay for detection of antibodies against Coccidioides in dogs and other mammalian species

et al. 2017

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Coccidioides is a soil-dwelling fungus that causes coccidioidomycosis, a disease also known as Valley fever, which affects humans and a variety of animal species. Recent findings of Coccidioides in new, unexpected areas of the United States have demonstrated the need for a better understanding of its geographic distribution. Large serological studies on animals could provide important information on the geographic distribution of this pathogen. To facilitate such studies, we used protein A/G, a recombinant protein that binds IgG antibodies from a variety of mammalian species, to develop an enzyme immunoassay (EIA) that detects IgG antibodies against Coccidioides in a highly sensitive and high-throughput manner. We showed the potential of this assay to be adapted to multiple animal species by testing a collection of serum and/or plasma samples from dogs, mice, and humans with or without confirmed coccidioidomycosis. We then evaluated the performance of the assay in dogs, using sera from dogs residing in a highly endemic area, and found seropositivity rates significantly higher than those in dogs of non-endemic areas. We further evaluated the specificity of the assay in dogs infected with other fungal pathogens known to cross-react with Coccidioides. Finally, we used the assay to perform a cross-sectional serosurvey investigating dogs from Washington, a state in which infection with Coccidioides has recently been documented. In summary, we have developed a Coccidioides EIA for the detection of antibodies in canines that is more sensitive and has higher throughput than currently available methods, and by testing this assay in mice and humans, we have shown a proof of principle of its adaptability for other animal species.

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Section: Introductionmentioning

confidence: 99%

Development of an enzyme immunoassay for detection of antibodies against Coccidioides in dogs and other mammalian species

et al. 2017

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“…We sought therefore to determine in the present study if this concentration of ketoconazole or miconazole altered the structure of the different morphologic phases of C. immitis. Recent publications [21,22] have described the saprobic and parasitic forms of C. immitis in clear detail and have updated earlier morphologic studies [5, 6, 10, 19] on C. immitis.On the other hand, surface characteristics of C. immitis, as seen with scanning electron microscopy, have not been reported in detail. We have therefore limited our descriptions in this paper to developmental changes in fungal structure during normal growth and to alterations that occur after exposure of the organism to miconazole and ketoconazole.…”

mentioning

confidence: 96%

mentioning

confidence: 97%

Ultrastructure ofCoccidioides immitisafter exposure to the imidazole antifungals miconazole and ketoconazole

Borgers¹,

Levine²,

Cobb³

1981

Med Mycol

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Scanning and transmission electron microscopy was performed on the various phases ofCoccidioides immitis, exposed for different periods of time to the imidazole antifungals miconazole and ketoconazole.The development of spherules into endospores, which takes place in cultures under normal growth conditions, was suppressed in the drug treated cultures.Typical ultrastructural changes were localized at the cell periphery and in the vacuolar system. The drugs did induce changes in mature, resting endospore cultures and in cultures incubated statically at room temperature. Aerobically growing endospores were not susceptible to either drug. The transformation of arthroconidia into mycelium was fully prevented after treatment. Mycelial cells were most susceptible to the antifungals for necrosis was induced in a substantial part of the hyphae after exposure for 24 h.The imidazole drugs, miconazole and ketoconazole, interfere markedly with progressive murine coccidioidomycosis [13][14][15]17]. Treatment, after intranasal instillation of arthrocondia, limits the subsequent replication of the spheruleendospore phase of Coccidioides immitis in the lungs. Early ketoconazole treatment, in particular, markedly reduces dissemination 1-13, 15] characterized by fungal invasion of the peritoneal organs. These activities are associated with high rates of survival in appropriately treated animals. Corresponding findings in man [12,20,23] also indicate that the drugs are effective in local and in disseminated coccidioidomycosis. However, in animals, as in man, biocure rates are low and prolonged therapy is required.In animals it was apparent that exposure of endospores to plasma concentrations of ketoconazole of 10#gml-1 was therapeutically beneficial [15]. We sought therefore to determine in the present study if this concentration of ketoconazole or miconazole altered the structure of the different morphologic phases of C. immitis. Recent publications [21,22] have described the saprobic and parasitic forms of C. immitis in clear detail and have updated earlier morphologic studies [5, 6, 10, 19] on C. immitis.On the other hand, surface characteristics of C. immitis, as seen with scanning electron microscopy, have not been reported in detail. We have therefore limited our descriptions in this paper to developmental changes in fungal structure during normal growth and to alterations that occur after exposure of the organism to miconazole and ketoconazole.

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“…The conidia were suspended in fixative solution and prepared for the SEM in the Millipore Swinny apparatus using a 1.0-f.Lm-pore-diameter Nuc1eopore filter. The fractured ends and outer sleeve of wall material visible in Figure 19 are characteristic of this kind of conidium (Sun et al, 1979;. (Figure 19), were collected on Nucleopore filters (2.0-and 0.5-fLm pore diameter, respectively).…”

Section: Cell Suspensionsmentioning

confidence: 99%

Preparation of Microfungi for Scanning Electron Microscopy

Cole

1986

Ultrastructure Techniques for Microorganisms

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Electron microscopic studies of saprobic and parasitic forms ofCoccidioides immitis

Cited by 37 publications

References 32 publications

Development of an enzyme immunoassay for detection of antibodies against Coccidioides in dogs and other mammalian species

Development of an enzyme immunoassay for detection of antibodies against Coccidioides in dogs and other mammalian species

Ultrastructure ofCoccidioides immitisafter exposure to the imidazole antifungals miconazole and ketoconazole

Preparation of Microfungi for Scanning Electron Microscopy

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