Spore ultrastructure in Sporothrix schenckii

Pathogenic strains of Sporothrix schenkii may show triangular spores, whose angular shape is maintained by a tiebeam effect in the inner cell wall structure. This difference in wall structure lies adjacent to a folded and possibly more active part of the spore cytoplasm. The supposed generation of asci in old cultures was simulated by the death of hyphae which are reinvaded by intrahyphal growth with intrahyphal spore production, while true asci were not seen.     

Effect of porphyrins and their derivatives on biosynthesis of vitamin B 12 and the development of Propionibacterium shermanii]

The effect of uroporphyrin, coproporphyrin and their cobalt-containing derivatives on the biosynthesis of vitamin B12 and development of propionibacterium shermanii was studied. The compounds under study stimulated the vitamin synthesis by growing cultures and resting suspensions of these bacteria. Cobalt porphyrins as the sole source of cobalt were used in the vitamin B12 biosynthesis. An addition of cobalt porphyrins to the growing culture of propionic bacteria increased in accumulation of their biomass. Possible mechanisms of porphyrin involvement in the biosynthesis of vitamin B12 and the specific role of cobalt porphyrins in the bacterial activity are discussed.     

Autoradiographic model experiments with 67Ga and 99mTc

Summary In order to evaluate the feasibility to localize correctly ⁶⁷Ga citrate and ^99mTc pertechnetate in tissues, the resolution of these radioactive compounds were measured in a model system using four different autoradiographic techniques, wet as well as dry.Wet autoradiographic techniques gave an almost complete loss of ⁶⁷Ga. In deparaffinized sections of fixed and paraffin-embedded tissue the remaining ⁶⁷Ga, which was probably bound to proteins, gave a resolution of 2.6 . ^99mTc was either completely lost in wet techniques or the procedure could not be performed at all because of the very short half life of ^99mTc.The resolution of ⁶⁷Ga in a dry autoradiographic technique (according to Stumpf) was 6.9 and the resolution of ^99mTc 22.6 .The technique in which frozen sections are thawed on dry film and consequently dryed, gave slightly better resolutions than the dry technique (according to Stumpf) with ⁶⁷Ga as well as ^99mTc.It is concluded that for the histological localization of ⁶⁷Ga and ^99mTc a dry technique is required. However, the use of a wet technique can be considered, provided a loss of the radioisotope is acceptable and the procedure is controlled by a dry technique.     

Plant desiccation and protein synthesis: an in vitro system from dry and hydrated mosses using endogenous and synthetic messenger ribonucleic Acid

The conditions and requirements for an in vitro protein synthesizing system from the moss Tortula ruralis are outlined. Using this system the effects of desiccation, achieved quickly or slowly, were studied. Slowly dried moss retained fewer polyribosomes on desiccation but more active ribosomes than rapidly dried moss. Even in the completely desiccated moss the polyribosomes and/or free ribosomes present have retained their synthetic capacities. On rehydration, the slowly dried moss resumed protein synthesis more quickly than moss previously desiccated rapidly. Moss ribosomes are cycloheximide sensitive and chloramphenicol insensitive and thus the major protein synthesis occurs within the cytoplasm on rehydration. Extracted polyribosomes per se can withstand desiccation to a significant extent, suggesting that protection by the cytoplasm might not be necessary. The aquatic moss Hygrohypnum luridum can retain polyribosomal and ribosomal activity during desiccation, but this decreases greatly on rehydration.     

Neurophysiologic mechanisms of the formation of the signal significance of words in yound children]

It has been established by means of the auto- and cross-correlation EEG analysis of children in the second year of life that different functional systems of relationships of cortical structures are formed during the word perception depending on whether it is an indifferent or signal stimulus for the child. In response to indifferent words, synphasic oscillations of the biopotentials appear in the infero-parietal and temporal, as well as in the temporal and frontal zones of the dominant hemisphere, without enhancement of the periodic processes and without appearance of a common rhythm. Signal verbal stimuli produce enhanced highly synchronous, synphasic interconnections of the infero-parietal biopotentials not only with temporal, but more considerably so with the frontal activity of the left hemisphere. This is accompanied by increased periodicity of processes between them and the appearance of a predominant rhythm 4--5 osc/sec.