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The effects of a Plagiorchid metacercaria upon certain tissues of the snail Vivipara bengalensis (Lamarck) have been studied. In the mantle it would possibly interfere with the normal elastic function of the organ. In the tentacle the cysts are very likely to interfere with the normal sensory function of the organ, the vision of the host and also with the fertilizing power of the male individuals. The cysts in the gill would possibly interfere with the usual course of the blood and also with the normal respiratory function of the organ. [ABSTRACT FROM AUTHOR]

Trace elements were required by Aspergillus melleus and A. ochraceus, but not by A. sulphureus, to grow and to elaborate ochratoxin A. The composition of the medium affected the synthesis of the toxin more than the growth of the mycelium.

Earlier electrophoretic analyses have shown that the 60-70S RNA of avian sarcoma viruses contains a characteristic subunit, termed class a subunit, which has a lower electrophoretic mobility than class b subunit found in transformation-defective derivatives of sarcoma viruses and in avian leukosis viruses. We have compared the RNAs of three nondefective avian sarcoma viruses, B77 and Prague and Schmidt-Ruppin strains of Rous sarcoma virus, with those of their transformation-defective (td) derivatives, td B77, td PR-C, and td SR-A, respectively, to determine the chemical basis for the difference between class a and b subunits. It was found by "fingerprinting" that (1) all (about 20-25) large T1 RNase-resistant oligonucleotides present in class b subunits of transformation-defective viruses have homologous counterparts in the class a subunits of corresponding nondefective sarcoma viruses and that (2) class a subunits contain a few (one or two) additional oligonucleotides that are not present in class b. By contrast the oligonucleotide fingerprints of avian tumor viruses of different strains and subgroups were very different.Cross hybridization of classes a and b RNA of sarcoma virus B77 with DNA transcribed from a corresponding transformation-defective virus td B77 showed that the two RNAs share at least 60% and differ by about 10% of their sequences. It is suggested that the structural relationship of class a and b subunits of corresponding viruses may be expressed as a = b + x, and that all the oligonucleotides present only in RNAs of sarcoma viruses but not in transformation-defective viruses of the corresponding strains are part of sequence(s) x. The possibility that x represents genetic information directly or indirectly involved in transformation of fibroblasts is discussed.