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Cell wall-deficient forms of Mycobacterium smegmatis were produced in growth medium containing D-cycloserine and horse serum. These cells were transformed into protoplasts with EDTA and lysozyme. Subsequent lysis by nucleases followed by osmotic shock produced membrane vesicles (whole cell ghosts).

The interaction of aflatoxin B1 with a number of biologically important substances has been investigated by spectrophotometric and fluorimetric techniques. The ultra-violet absorption of tryptophan, adenosine, RNA and DNA were altered by the addition of aflatoxin B1. Some amino-acids, purine and pyrimidine derivatives, bovine-serum albumin and DNA quenched the fluorescence of aflatoxin B1. Fluorescence polarization data suggested that the interaction of aflatoxin B1 with bovine-serum albumin was stronger than that with DNA.

Young, weanling rats fed wheat as a sole source of protein have been shown to develop periportal liver lipid infiltration. An attempt has been made to study the mechanism by which these lipid changes are produced. Weanling, male albino rats were fed three diets containing 10% protein based on wheat, wheat fortified with 0.2% lysine or casein, as control. Plasma and liver lipids, incorporation of [1-(14)C]acetate and [U-14C]glucose into hepatic lipids and triglycerides were studied after 6 weeks of feeding. Results of radioactive incorporation studies indicated that hepatic lipogenesis was depressed in rats fed wheat diets. However, adrenal cortical function as well as increased mobilization of lipids from adipose tissue was observed in these rats. Impaired secretion of lipids from liver to plasma is another factor which may be responsible for hepatic lipid accumulation in rats fed the lysine-deficient diet. Rats fed the lysine fortified wheat diet represented a more normal metabolic state though some features of protein deficiency were evident in this group too.

The in vivo effect of a single oral dose (30mg/kg body weight) of dieldrin on proteolipid and phosphatidopeptide content of liver and brain and on total protein of liver, brain, plasma, muscle and kidney of rat was studied. Incorporation of (14C)leucine into total protein of liver was increased whereas labelling of total protein of muscle was decreased. Labelling of total protein of other tissues was unchanged. Incorporation into liver phosphatidopeptides was increased and this was consistent with an involvement of group. Proteolipid protein content of brain was increased and that of liver unchanged. There was, however, no change in the labelling of brain or liver proteolipids.

The effects of various factors, such as pH, buffer, sodiumchloride and ultra-violet radiation on the fluorescence of aflatoxins B1 and G1 have been studied. The fluorescence characteristics of aflatoxins B1 and G1 underwent a marked change at pH values above 7.2. Prolonged exposure to ultra-violet radiation lead to some degradation of aflatoxins and the extent of degradation was dependent upon the nature of the solvent. Sodium chloride partially protected the toxins from degradation by ultra-violet radiation or alkaline conditions.

Uptake of radioactive tryptophan by Mycobacterium tuberculosis H(37)Rv grown in vitro and in vivo was investigated. K(m) values indicated low affinity, and sodium azide inhibited uptake. Rifampin at the minimal inhibitory concentration had no effect, whereas ethambutol inhibited uptake only in the bacilli grown under in vitro conditions. The significance of these results is discussed.

Sputum collected from patients with respiratory diseases were examined for presence of benzo(a)pyrene hydroxylase (BPH) activity. The human bronchial mucus used in these studies had significant capability to metabolize benzo(a)pyrene. Clarification of the sputum by agents such as N-acetylcysteine or pancreatin in presence of antibiotics was found to be essential for the detection of BPH activity. In vitro incubation of the clarified human bronchial mucus with benzoflavone caused inhibition, while 7,8-dimethyl-benzanthracene induced BPH enzyme activity.

Aspergillus parasiticus ATCC 15517 produced 28 to 30 mg of aflatoxin per 100 ml of a medium containing sucrose, asparagine, and salts in stationary and shaken cultures. In the absence of asparagine in the medium, the toxin yields fell drastically, and the thin-layer chromatograms of the chloroform extracts of the cultures indicated the total absence of aflatoxin G(1) and the presence of new intense blue and green fluorescent bands having R(F) values lower than aflatoxins. Initial pH was critical and had to be around 4.5 for good growth and high toxin production on this medium. Optimum concentrations of KH(2)PO(4) and MgSO(4).7H(2)O in the medium were much lower than those normally used in fungal growth media.