The NAM8 gene in Saccharomyces cerevisiae encodes a protein with putative RNA binding motifs and acts as a suppressor of mitochondrial splicing deficiencies when overexpressed.

Summary We have characterized the nuclear geneNAM8 inSaccharomyces cerevisiae. It acts as a suppressor of mitochondrial splicing deficiencies when present on a multicopy plasmid. The suppressed mutations affect RNA folding and are located in both group I and group II introns. The gene is weakly transcribed in wildtype strains, its overexpression is a prerequisite for the suppressor action. Inactivation of theNAM8 gene does not affect cell viability, mitochondrial function or mitochondrial genome stability. TheNAM8 gene encodes a protein of 523 amino acids which includes two conserved (RNP) motifs common to RNA-binding proteins from widely different organisms. This homology with RNA-binding proteins, together with the intronic location of the suppressed mitochondrial mutations, suggests that the NAM8 protein could be a non-essential component of the mitochondrial splicing machinery and, when present in increased amounts, it could convert a deficient intron RNA folding pattern into a productive one.     

The flow of jelly within a honeybee colony

Summary The flow of jelly from 100 nurse bees to the members of two normal-sized colonies was measured during one night. To follow the flow, nurses were injected with ¹⁴C-phenylalanine. They incorporated this label into the protein of their hypopharyngeal (brood food) glands and their own body protein. When they were allowed trophallactic contacts during the investigation period a loss of label and a shift away from the abdomen was observed, indicating protein synthesis in the hypopharyngeal glands from previously stored protein. Very young larvae were fed less frequently than older ones. Younger workers received larger amounts of jelly than older ones, but considerable amounts were given to foragers. Drones behaved similarly. Between one-third and one-half of the distributed jelly was given to imagines; 10% and 16% of all workers received radioactive jelly from 100 nurses in the two colonies during one night. Thus, jelly is a very important food for adult honey bees. There was a remarkable exchange of label within the class of nurses themselves that is interpreted as communication within the social system.Abbreviation dpm decays per minute     

A note on the structure of tail hairs from a pygmy hippopotamus (Choeropsis liberiensis)

The pygmy hippopotamus (Choeropsis liberiensis), like the Nile hippopotamus (Hippopotamus amphibius), defecates by backing into vertical objects while making a series of rapid, propellerlike tail movements that spread a mixture of urine and feces in a wide swath. Split hairs from the distal ventral surface of the pygmy hippopotamus tail were studied with the scanning electron microscope to determine whether the splitting was a normal character of the hair or was due to damage. The results suggest that splitting is a normal feature of the hair that may facilitate the dispersal of urine and feces.     

Plasminogen activator: The major secreted neutral protease of cultured skeletal muscle cells

Clonal mouse skeletal muscle cells which differentiate in culture and from synpases with neuronal cells were found to secrete high levels of protease activity as measured with an ¹²⁵I-fibrin assay. The secreted proteolytic activity was more than 90% dependent upon the presence of plasminogen in the medium, and had a pH optimum at 7 to 8. This activity was not inhibited by n-ethylmaleimide, pepstatin, EDTA, or EGTA. At millimolar concentrations, greater than 90% inhibition was obtained with either soybean typsin inhibitor, epsilon aminocaproic acid, Trasylol, or leupeptin. Almost complete inhibition occured with 1 mM diisopropylfluorophosphate suggesting the presence of a serine residue at the catalytic site. In contrast to the high levels of secreted activity, a lower steady-state level of cell-associated protease activity was detected in cell lysates. The high level of plasminogen activator secreted into the medium of cultured muscle cells suggests a role for such extracellular protease activity in myogenesis during development and remodeling following muscle injury. Such information may be useful in understanding the initial degeneration of neuromusclar contacts in experimental and pathologic denervation.     

Der informationsgehalt des intrazellularwassers und die informations-speicherung in der embryo- und Phylogenese

The nucleo-free erythrocyte is presented as the simplest differentiated cell whose energy-exchange has the single purpose of preserving the cell structure; this structure is based on the regular quasi-crystalline state of intracellular water, which is expressed by the negative entropy(-S _W )and the temperature T _W which is higher than the temperature of the extracellular water T. The information content of intracellular water, J _W is proportional to the temperature difference: J _W T=T _W -T. The regular state of intracellular water is maintained by the basal metabolism that takes place in the membrane of the differentiated cell. The energy exchange, i.e., the absorption of free energy and the liberation of an equivalent amount of heat, occurs in the form of work cycles of the enzym-water-complexes in the cell membrane. The differentiated cell of the multicellular animal organism is the result of embryogenetic processes accompanied by heat-liberation. The specific heat-liberation, i.e., the heat produced by a single cell, begins with a quasi-zero value of the fertilized egg cell and grows with acceleration to a maximum value at the end of embryogenesis. This process of acceleration of heat-liberation is caused by the entrance of the water from the outer medium into the embryonic cell; the water undergoes the phasechange fluid crystal with heat-liberation. The intracellular water within the embryonic cell becomes structurated; this is also accompanied by growing heatliberation. The thermodynamic characteristic of embryo genetic development is expressed by the principle of the maximum of velocity of entropy production of the cell at the end state of the process of differentiation. This principle applied to phylogenetics, leads to the formulation of the principle of accumulation of biological information: J(t). In the course of evolution living systems are able not only to store information of past generations, but also to create information: J(t)e^Intl where t is the time of phylogenesis.