Attempts to breed the nine-banded armadillo (Dasypus novemcinctus) in captivity--a preliminary report.

Three pairs of nine-banded armadillos were successfully kept in wire-fenced pens in natural surroundings with light, temperature, and weather as in the farms of Louisiana, a natural habitat of armadillos. One female delivered quadruplets after being in the experimental pen for 10 months and 11 days. It is possible that in this experiment breeding of nine-banded armadillos in captivity has been achieved under controlled conditions for the first time.

An alternative route for infecting armadillos with Mycobacterium leprae.

A nine-banded armadillo was inoculated with Mycobacterium leprae in both hind footpads. The animals were usually inoculated intravenously, or intradermally in the abdominal skin. Profuse multiplication of the bacilli occurred at the injection sites after more than two years. Eventually bacteraemia developed, and large numbers of the organisms were found in skin biopsies and in lymph nodes. There was limited dissemination of the bacteria into the spleen and the liver, and peripheral nerve invasion by the bacilli was also detected. M. leprae remained viable in the liver tissue, kept frozen at -80 degrees C for three years. This experimental system would be useful in testing the effects of certain immunological and chemotherapeutic agents against M. leprae by injecting them directly at the infection site.

Variable lepromin response to Mycobacterium leprae in resistant armadillos.

Eight armadillos resistant to the infection of Mycobacterium leprae were lepromin tested. The tissue response was tuberculoid in 5, borderline in 2, and lepromatous in 1, thus showing a wide variation. It is seen that although cell-mediated immunity as evidenced by a tuberculoid granulomatous response to killed M. leprae is associated with resistance to the disease, there may be other yet unknown factors which protect armadillos from the infection. Lepromin responses were recognized histologically even at a low dose of 10(3) organisms, and the response increased with the dose up to 10(7) organisms. The tissue reaction to live organisms was the same as that to killed ones, and autoclaving of M. leprae produced no change in the tissue response to the antigens of M. leprae.

Glutamic acid decarboxylase in Mycobacterium leprae.

Suspensions of Mycobacterium leprae purified from the organs (mostly spleen) of experimentally-infected armadillos (Dasypus novemcinctus, Linn) decarboxylated 1-(14C) glutamic acid liberating 14CO2. The reaction was pyridoxal phosphate-dependent and was inhibited by hydroxylamine, suggesting that it is a true amino acid decarboxylase. Loss of the activity at higher temperatures indicated the enzymatic nature of the reaction. Excess substrate or substrate analogs inhibited the decarboxylase whereas alpha-ketoglutarate and glutarate stimulated it. The activity was four times higher at pH 4.5 than at pH 6.8, suggesting that the enzyme is of microbial origin and not derived form the host cells. Armadillo spleen did not decarboxylate the amino acid. The Km value of the enzyme in the organisms was similar to that in Escherichia coli. The results reported here show that glutamate decarboxylase (EC 4.1.1.15) is an inherent metabolic activity of M. leprae, and might explain its unusual neural affinity. Glutamic acid is the most abundant amino acid occurring in the nerve tissue.

Borderline leprosy in an experimentally infected armadillo.

Out of six armadillos infected intravenously with 4.66 x 10(8) M. leprae, one developed a delayed hypersensitivity tissue response with the formation of an epithelioid cell granuloma. It is suggested that, although 80% of armadillos are susceptible to infection with M. leprae, some among these susceptible ones will exhibit varying degrees of delayed hypersensitivity reactions. These animals may go through a borderline phase before ultimately undergoing lepromatous degeneration.

DNA isolated from Mycobacterium leprae: genome size, base ratio, and homology with other related bacteria as determined by optical DNA-DNA reassociation.

DNA derived from Mycobacterium leprae (grown in armadillos) was isolated, purified, and analyzed spectrophotometrically. The genome size and guanine-plus-cytosine content of M. leprae were 1.3 X 10(9) and 55.8%, respectively. Among selected strains of mycobacterial, nocardial and corynebacterial species, Corynebacterium sp. 2628 LB, isolated from a human leprosy patient, showed the highest DNA homology with M. leprae. Of the DNAs derived from mycobacteria, those of M. tuberculosis and M. scrofulaceum showed a comparatively high reassociation with the DNA of M. leprae.

Tissue response to lepromin, an index of susceptibility of the armadillo to M. leprae infection--a preliminary report.

In this preliminary report the histopathological appearance of the lepromin reaction in armadillos was correlated with their response to infection with M. leprae. Three different types of lepromin response were described, namely the lepromatous, the borderline, and the tuberculoid lepromin reactions. It was found that 10 out of the 11 animals with a lepromatous lepromin reaction and the one animal with a borderline lepromin reaction developed disseminated disease. The two with a tuberculoid lepromin reaction and one of the 11 with a lepromatous lepromin reaction failed to develop leprosy. It is suggested that by using the lepromin response it is possible to assess, to a great extent, the susceptibility of armadillos to infection by M. laprae. The pros and cons of using the armadillo as an animal model for a vaccine trial are briefly discussed.

DNA isolated from Mycobacterium leprae: genome size, base ratio, and homology with other related bacteria as determined by optical DNA-DNA reassociation.

DNA derived from Mycobacterium leprae (grown in armadillos) was isolated, purified, and analyzed spectrophotometrically. The genome size and the guanine-plus-cytosine content of M. leprae were 1.3 x 10(9) and 55.8%, respectively. Among selected strains of mycobacterial, nocardial, and corynebacterial species, Corynebacterium sp. 2628 LB, isolated from a human leprosy patient, showed the highest DNA homology with M. leprae. Of the DNAs derived from mycobacteria, those of M. tuberculosis and M. scrofulaceum showed a comparatively high reassociation with the DNMA of M. liprae.