Occurrence of killer yeasts in leaf-cutting ant nests

Killer activity was screened in 99 yeast strains isolated from the nests of the leaf-cutting ant Atta sexdens against 6 standard sensitive strains, as well as against each other. Among this yeast community killer activity was widespread since 77 strains (78%) were able to kill or inhibit the growth of at least one standard strain or nest strain. Toxin production was observed in representatives of all the studied genera including Aureobasidium, Rhodotorula, Tremella and Trichosporon, whose killer activity has not yet been described.

[Diagnostic possibilities and limitations of the necropsy examination on cadavers exhumed because of sudden cardiac death]

After presenting five individual cases, the authors confirm the possibility of a diagnosis of sudden cardiac death where myocardial and/or coronary arteries lesions were present, by performing an exhumed body's autopsy even after a considerable amount of time after death. With regard to this procedure, performed only by experienced consultants specializing, a particularly accurate verification is necessary.

Cellulose degradation by Leucocoprinus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens rubropilosa

Leucocoprinus gongylophorus, the fungus cultured by the leaf-cutting ant Atta sexdens rubropilosa, is able to degrade efficiently cellulose, microcrystaline cellulose, carboximethylcellulose, and cellobiose. Analysis of the degradation products indicate that the fungus produce extracellular beta-glucosidase, exo- and endo-glucanase. The importance of cellulose degradation to the association of fungus and ant is discussed.

Distribution of the iron-heme displacement as resulting from myoglobin conformational substrates: an AOM approach to the interpretation of the EPR spectra

The electron paramagnetic resonance (EPR) low-temperature spectra of high spin ferric myoglobin samples in different solvent composition have been analyzed in terms of a distribution of the energy differences delta 1 and delta 2 for the iron low-lying electronic states. The widths of these distributions, which are found to be dependent on the solvent composition, have been correlated to the presence of a frozen ensemble of conformational substrates. A dedicated analysis based on the angular overlap method (AOM) has allowed us to work out a quantitative relationship between the delta 1 and delta 2 distributions and the spread of the iron-heme displacement; this being a structural parameter relevant for the biological functionality of the protein. The observed dependence of the iron-heme displacement distribution on the solvent composition is discussed.

UV excitable fluorescence of lumirubin

Solutions of bilirubin in different solvents show negligible fluorescence when they are excited with UV light. After irradiation, blue-violet fluorescence (400-450 nm) is observed, whose intensity and peak position depend on the irradiation time. The isolation of pure lumirubin led us to attribute this fluorescence specifically to this photoisomer, even if small contributions from other photoproducts cannot be ruled out. The emission peak of the pure lumirubin in aqueous solution (phosphate buffer) is at 415 nm while the main excitation peak is at 315 nm. Finally, an interpretation of the observed fluorescence is proposed on the basis of the similarity of the present results with previously reported experimental data.

Masturbation injury resulting from intraurethral introduction of spaghetti

A singular case of masturbation by endourethral introduction of a piece of spaghetti is reported. We became aware of the case because fragmentation of the spaghetti caused a cicatricial stenosis of the urethra that required surgical treatment.

Chain link fence impalements in a traffic accident

The impalement of two occupants of a car on chain link fencing during a single-vehicle accident is described. The reexamination of the survivor after 10 months is presented. The Italian Penal Code requirements are discussed regarding the examination of injured persons from the medicolegal standpoint.

Procarbazine hydrochlorate carcinogenesis in Osborne-Mendel rats

3 mg/day procarbazine hydrochlorate, in a total dose of 300 mg, provoked tumours or raised their number in a variety of rat organs and tissues. 70.8% males and 92.5% females bore tumors against 16.6 and 33% of the controls. It is suggested that the lack of a specific target organ is due to the metabolic conversion of procarbazine to alkylating agents in the liver. The chemical structure, distribution of these agents within the organism and the different organ-specific enzyme activation and inhibition systems are probably responsible for the variable organotropism.

Emission spectra from copper proteins containing type-3 centres

Aqueous solutions of copper-proteins containing type-3 centres (ceruloplasmin, tyrosinase, haemocyanin), excited within their absorption bands at 325-345 nm, show typical luminescence spectra. The emission bands peak at 415-445 nm and their decay time is no longer than 10 ns. A strong analogous fluorescence is obtained also by excitation of concentrated solutions of carboxylic acids and amino acids, which show again absorption bands around 330 nm. Such a fluorescence, although less intense, is also observed in copper(II) carboxylate solutions. In contrast, no fluorescence has been recorded in solutions of acetic anhydride and of polypeptides (valinomycin, gramicidin D), which do not have free carboxyl groups. We tentatively attribute this novel fluorescence in the investigated copper proteins to interactions between carboxyl groups of amino acids at, or near, the active site.

Lung carcinogenesis by procarbazine chlorate in BALB/c mice

A study of the carcinogenic action of procarbazine chlorate in BALB/c/Cb/Se mice showed that this substance significantly increases the incidence or lung tumours in both sexes. The induced tumors were alveolar-lining, papillary and alveolar-papillary type carcinomas with a tendency to invade the bronchial wall.

Jahn-Teller effect in biomolecules

The role played by the Jahn-Teller effect for a correct interpretation of the spectroscopic and structural data of some biological systems is stressed and a short review of the investigations so far performed is presented. Afterwards, on the basis of the angular overlap model, several expressions are given for the coupling constants of the transition metal ions, which mainly occur in biomolecules (Fe, Co, Cu, Mo) in order to have an approximate evaluation of the Jahn-Teller effect magnitude. The above expressions are then applied to obtain the vibronic coupling constants of the deoxygenated hemoglobin and myoglobin. The results obtained are compared with the predictions previously made by the author on these systems.