Metabolism of mannitol by Coccidioides immitis

Lones, George W. (National Institute of Allergy and Infectious Diseases, U.S. Public Health Service, Bethesda, Md.), and Carl Peacock. Metabolism of mannitol by Coccidioides immitis. J. Bacteriol. 87:1114-1117. 1964.-Strain M-11 of Coccidioides immitis was found to utilize mannitol for growth in the mycelial form but not in the spherule form. Cell-free extracts of both forms, grown on glucose, were capable of reducing nicotinamide adenine dinucleotide with mannitol-1-PO(4) but not with mannitol. The extracts accomplished a rapid oxidation of reduced nicotinamide adenine dinucleotide by fructose-6-PO(4), the expected product of mannitol-1-PO(4) oxidation. Fructose was inactive. Paper electrophoresis and chromatography with several solvent systems demonstrated a substance in extracts of both mycelium and spherules having a migration consistent with that of mannitol.     

Conversion of Coccidioides immitis in tissue culture

Summary Utilization of a pre-treatment resulted in the establishment of a simple technique to enhance spherulation ofC. immitis in tissue culture.Establishment of the fact that culture spherules are produced from mycelial elements was also recognized and should be included in the life cycle ofC. immitis when cultured in vitro.     

Solid-phase immunoenzyme analysis of Coccidioides immitis antigens

A highly effective and specific solid-phase enzyme immunoassay system has been developed. The enzyme immunoassay is a highly sensitive technique for the detection and identification of C. immitis cellular and metabolic antigens. This technique is suitable for the study of strain differences in the antigenic composition of C. immitis, rendered harmless by different methods. The expediency of the preliminary sonification of cell suspensions of C. immitis, the causative agent of coccidioidomycosis, has been experimentally confirmed.     

Elastase activity of fungi with anamorphs similar to Coccidioides immitis

The elastin digestion assay was examined to determine if it would facilitate the identification of Coccidioides immitis when non-pathogenic fungi resembling C. immitis are encountered. Fungal isolants tested have anamorphs that closely resemble the macroscopic or microscopic morphology of C. immitis. Elastin hydrolysis was measured by elastin-agar plate assays. Approximately 80% of the isolants hydrolyzed elastin; thus, the elastin digestion assay as a differential test appears to have little value.     

Interaction of human peripheral blood mononuclear cells with Coccidioides immitis arthroconidia

We explored the in vitro interaction of human peripheral blood mononuclear cells with the arthroconidial stage of the fungus Coccidioides immitis. Fresh peripheral blood monocytes in an adherent monolayer were capable of ingesting C. immitis. Further, peripheral blood monocytes from either skin-test-positive or skin-test-negative donors significantly decreased the in vitro growth of C. immitis when coccidioidal arthroconidia were incubated with monocytes. Peripheral blood mononuclear cells also reduced fungal incorporation of the chitin precursor N-acetyl glucosamine. Cell fractions consisting predominantly of monocytes were significantly more active in this regard than fractions containing predominantly lymphocytes. Moreover, this activity was independent of the coccidioidal skin-test status of the donor. We conclude that human fresh peripheral blood mononuclear cells are able to phagocytize C. immitis arthroconidia and have the ability to inhibit its growth in vitro. That these abilities are independent of the immune status of the donor supports the possibility that the peripheral blood monocyte may contribute to the early defense against initial coccidioidal infection.     

Serological Comparison of Spherules and Arthrospores of Coccidioides immitis

Spherule and arthrospore cellular preparations were sonic-treated and separated into their respective supernatant and sediment components. Complement-fixation tests with antispherule and antiarthrospore pooled rabbit sera revealed that the soluble antigens exhibited more serological activity than the sediment preparations. After autoclaving, an arthrospore cellular antigen exhibited increased activity with either antisera, whereas autoclaved spherules exhibited increased activity only with antispherule serum. Complement-fixation tests with coccicioidin and spherule culture supernatant preparations revealed quantitative or qualitative differences in antigenic determinants between these two morphological phases of Coccidioides immitis.     

Morphogenesis throughout saprobic and parasitic cycles of Coccidioides immitis

The fungus, Coccidioides immitis, differs from other dimorphic pathogens in that its parasitic stage is a complex morphogenic cycle, raising the question that changes in structure and composition during morphogenesis might influence host responses. As a prelude to examining the interaction of fungal morphogenesis and host responses, the life cycle of this fungus has been examined in greater detail than previously accomplished. During saprobic development, alternating enterothallic arthroconidia are formed as infectious propagules. The outer wall is broken and loosely adherent. Under in vitro conditions supporting the parasitic cycle, multinucleate arthroconidia transform into uninucleate round cells. Rapid, synchronous, nuclear replication is initiated, accompanied by increase in cell mass and deposition of new cell wall substance. As karyokinesis ceases, morphologic differentiation begins with invagination of the inner layers of the spherule wall and then is progressive, eventually segmenting the protoplasm into uninucleate endospores grouped in clusters within a hyaline membrane. Endospores, escaping through a break in the spherule wall, are held in aggregates by fibrils which are stretched and broken as endospores separate. It would seem that rapid production of hundreds of progeny from an original single cell, protected during development by an enclosing spherule wall and then released in clusters, should favor establishment of the fungus in a host, and dynamic changes in the cell wall during morphogenesis should influence the host response.     

Isolation and identification of Coccidioides immitis from natural sources

The review of media and techniques that have been developed to date appears to provide more than adequate choice for investigators in endemic areas to perform ecological studies of this organism. The final identification of this organism still lies in the demonstration of itsin vivo morphology.Paper read at the Eighth International Congresses for Tropical Medicine and Malaria, September 1968, Teheran (Iran).     

Isolation of coccidioides immitis from bat guano and preliminary findings on laboratory infectivity of bats with Coccidioides immitis

$\text{Coccidioides}$$\text{immits}$ has been isolated from the guano of bats obtained beneath bat roosting places deep within deserted mine tunnels. Certain species of bats have been demonstrated to be susceptible to experimental infection by $\text{C.}$$\text{immitis}$. There is, however, a difference in the laboratory susceptibility between the species studied ($\text{Antrozous}$$\text{pallidus}$ and $\text{Macrotus}$$\text{californicus}$). $\text{Antrozous}$$\text{pallidus}$ requires 8 times more arthrospores (400 as compared to 50) than does $\text{Macrotus}$$\text{californicus}$ to produce a defineable infection. Our cultures for $\text{C.}$$\text{immitis}$ in the tissue of $\text{Antrozous}$ produced colonies of the bacterium $\text{Serratia}$$\text{marcescens}$. Because these tissues were handled under sterile conditions the presence of this red pigment (prodigiosin) producing bacterium was thought not the result of contamination. Prodigiosin suggests a possible mechanism for the apparent greatly reduced susceptibility to $\text{C}$. $\text{immitis}$ found in the laboratory population of $\text{Antrozous}$. Skin and serological tests on bats were negative as were cultures of guano from experimentally infected bats and mice. It is speculated that infected dying bats that fall to the floor beneath their roosting sites may contaminate the guano. We of course realize that other animals (we have found $\text{Neotoma}$ and $\text{Bassariscus}$ rarely in these tunnels) may have tracked the fungus into these deep tunnel sites.