scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1948 ◽  
Vol 32 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Winston H. Price
Keyword(s):  
Microscopic Examination ◽  
Synthetic Medium ◽  
Bacterial Virus ◽  
Direct Microscopic Examination ◽  
Infected Cells

1. The release of S. muscae phage in veal infusion medium is correlated with lysis of the host. 2. The release of the bacterial virus in Fildes' synthetic medium occurs in a step-wise manner before observable lysis of the cells occurs. This result has been confirmed by both turbidimetric readings and direct microscopic examination of the infected cells.

scholarly journals PHAGE FORMATION IN STAPHYLOCOCCUS MUSCAE CULTURES

1950 ◽  
Vol 34 (2) ◽  
pp. 251-277 ◽  
Author(s):  
Winston H. Price
Keyword(s):  
Aspartic Acid ◽  
Phage Particle ◽  
Burst Size ◽  
Synthetic Medium ◽  
Acid Synthesis ◽  
Active Particle ◽  
Multiple Infection ◽  
Experimental Conditions ◽  
Virus Particles ◽  
Infected Cells

1. A strain of S. muscae which requires a substance present in certain acid-hydrolyzed proteins (AHPF) for virus liberation when singly infected in Fildes' synthetic medium no longer needs this substance when multiply infected. 2. In the absence of the AHPF under conditions of multiple infection the amount of phage released is approximately equal to the number of infecting particles between two to ten. Over ten particles per cell has no further effect on the yield of virus. 3. The experimental evidence indicates that it is the phage particle and not some other component in the lysate which can replace the AHPF. 4. The minimum latent period and rise period of cells singly infected in the presence of the AHPF and multiply infected in the absence of the AHPF are the same. 5. The desoxynucleic acid synthesis of cells, infected with a very few virus particles in the presence of excess AHPF and multiply infected with ten particles in the absence of the AHPF, occurs at approximately the same rate, with both infected samples synthesizing about the same amount of desoxynucleic acid and liberating the same yields of virus. 6. A strain of S. muscae which requires aspartic acid for virus synthesis when singly infected does not need this substance when multiply infected, the burst size under the latter conditions depending upon the multiplicity of infection between 3 to 12 particles per cell. 7. The data indicate that the virus released from multiply infected cells in the absence of added AHPF or aspartic acid is newly synthesized virus and not the original infecting particles. 8. The phage particle contains the AHPF and aspartic acid. 9. As a tentative working hypothesis, it is assumed that the AHPF and aspartic acid for phage formation under conditions of multiple infection, in the absence of added AHPF, or of aspartic acid, are contributed by the original infecting particles. 10. Ultraviolet-inactivated phage is adsorbed to the host cell and kills the cell although little virus is released under the experimental conditions. 11. Ultraviolet-inactivated phage particles, if added before the active particle is adsorbed, will greatly inhibit the liberation of new virus particles; but does not do so if added a few minutes after the active particle has been adsorbed. 12. Under the experimental conditions, reactivation of phage when present in multiply infected cells does not occur; and such ultraviolet-inactivated phage cannot serve as a source of the AHPF or aspartic acid, although the AHPF can be liberated from such inactivated particles by acid hydrolysis. 13. The results are discussed in relation to Luria's experiments with ultraviolet-treated phage and to his "gene pool" hypothesis of phage formation.

scholarly journals Diagnosis of Cutaneous Leishmaniasis in Colombia: the Sampling Site within Lesions Influences the Sensitivity of Parasitologic Diagnosis

2000 ◽  
Vol 38 (10) ◽  
pp. 3768-3773 ◽  
Author(s):  
José Robinson Ramírez ◽  
Sonia Agudelo ◽  
Carlos Muskus ◽  
Juan Fernando Alzate ◽  
Christof Berberich ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Microscopic Examination ◽  
Sampling Site ◽  
Parasite Load ◽  
Diagnostic Methods ◽  
Active Margins ◽  
Direct Microscopic Examination ◽  
Chronic Ulcers ◽  
Pcr Method ◽  
Higher Sensitivity

Parasitologic confirmation of cutaneous leishmaniasis is obligatory before chemotherapy can be considered. Direct microscopic examination of scrapings taken from indurated borders of ulcers has been routinely used as primary method of diagnosis. In this report we compared the sensitivity of examination of dermal scrapings taken from the bottoms of ulcers (BDS) with that of dermal scrapings taken from indurated active margins of lesions (MDS) in a total of 115 patients. The sensitivities of the microscopic examination were 90.4 and 78.3% for BDS and MDS samples, respectively. When the PCR method was used with a group of 40 patients, we also observed a higher sensitivity when BDS samples were examined (80.8% in BDS samples versus 57.7% in MDS samples). The improvement of the diagnostic sensitivity in the BDS samples appears to be related to the higher parasite load and more easily detectable morphology of amastigotes in the centers of the ulcers. Other parasitologic diagnostic methods, such as culture and histopathologic examination of biopsies, are less sensitive (67.5 and 64.3%, respectively). Aspirate culture, however, was shown to be the most sensitive method for the diagnosis of patients with chronic ulcers. When microscopic examinations of both MDS and BDS samples are combined, the sensitivity of diagnosis may rise up to 94%. We therefore recommend this method as a primary routine procedure for diagnosis of cutaneous leishmaniasis.

scholarly journals Simultaneous dermatophytosis and keratomycosis caused by Trichophyton interdigitale infection: a case report and literature review

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mingrui Zhang ◽  
Lanxiang Jiang ◽  
Fuqiu Li ◽  
Yangchun Xu ◽  
Sha Lv ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Microscopic Examination ◽  
Histopathological Examination ◽  
Trichophyton Mentagrophytes ◽  
The Body ◽  
Fungal Culture ◽  
Left Hand ◽  
Loss Of Vision ◽  
Trichophyton Interdigitale ◽  
Direct Microscopic Examination

Abstract Background Dermatophytosis is a fungal infectious disease caused by dermatophytes, which produce protease and keratinase to digest keratin, leading to the colonization, invasion, and infection of the stratum corneum of the skin, hair shafts, and nails. Trichophyton interdigitale belongs to Trichophyton mentagrophytes complex, which is the common pathogen causing dermatophytosis. Fungal keratitis, also called keratomycosis, is an infectious disease of cornea. Case presentation Here, we report a case of simultaneous dermatophytosis and keratomycosis caused by Trichophyton interdigitale. A 67-year-old man presented with extensive erythema all over the body since 4 years ago, fungal infection of left eye for 2 years, and loss of vision in the eye. These symptoms had become aggravated in the last month. Dermatological examinations showed extensive erythematous plaques with clear borders and scales, scattered red papules with ulceration, and scabs throughout the body. Onychomycosis was observed on the nails of left hand, conjunctival infection with secretion and loss of vision were noted in left eye. Hyaline septate hyphae were observed under direct microscopic examination, fungal culture and internal transcribed spacer sequencing revealed T. interdigitale. Histopathological examination suggested infectious granuloma. A diagnosis of dermatophytosis and keratomycosis caused by T. interdigitale with loss of vision in left eye was made. The patient was treated with luliconazole cream (two applications per day) and itraconazole (100 mg, BID, PO). Complete clinical remission was achieved after 1 month. Subsequently, the patient underwent left eye enucleation in the ophthalmology department. Conclusions In the present study, we reported a case of simultaneous dermatophytosis and keratomycosis caused by T. interdigitale, and reviewed the literature on corneal infection caused by Trichophyton. A total of 10 articles with 45 patients were published between 1973 and 2018. The pathogen of 27 patient were identified to species level. There were T. schoenleinii (17), T. mentagrophytes (4), T. verrucosum (3), T. rubrum (1), T. erinacei (1), and T. interdigitale (1). Five patients had corneal trauma, one had contact lens use history. Direct microscopic examination, fungal culture, and analysis of physiological characteristics were the main methods of identification. Early diagnosis and prompt treatment may help improve the management and outcomes.

Detection of latent murine nosematosis and growth of Nosema cuniculi in cell cultures

1970 ◽  
Vol 16 (4) ◽  
pp. 237-242 ◽  
Author(s):  
J. E. Bismanis
Keyword(s):  
Cell Culture ◽  
Infected Cell ◽  
Cell Cultures ◽  
Mouse Embryo ◽  
Microscopic Examination ◽  
Embryo Cell ◽  
Internal Organs ◽  
Persistently Infected ◽  
Mouse Embryo Cell ◽  
Direct Microscopic Examination

Administration of hydrocortisone to mice caused activation of latent nosematosis in at least 25% of the animals. The sporozoan parasite Nosema cuniculi could be demonstrated in the tissues of the internal organs and circulating blood by direct microscopic examination. Growth and multiplication of the parasite could be achieved in mouse embryo cell cultures, where the parasite infected and destroyed only about 2% of the cells, thus establishing a state of persistently infected cell culture. The parasite grown in cell culture retained its mouse pathogenicity.

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