Identification of two novel GTP-binding protein alpha-subunits that lack apparent ADP-ribosylation sites for pertussis toxin

Molecular cloning of cDNAs encoding alpha-subunits of guanine nucleotide-binding regulatory proteins (G-proteins) has revealed the existence of nine species of alpha-subunits. We have identified two additional G-protein alpha-subunits, which we refer to as GL1 alpha and GL2 alpha, by isolating bovine liver cDNA clones that cross-hybridized at reduced stringency with bovine Gi1 alpha-subunit cDNA. The deduced amino acid sequences of GL1 alpha and GL2 alpha share 83% identity with each other and show 45-55% identity with those of other known G-protein alpha-subunits. Both GL1 alpha and GL2 alpha lack a consensus site for ADP-ribosylation by pertussis toxin. Messenger RNA corresponding to GL2 alpha was detected in all tissues examined, but GL1 alpha mRNA was detected only in liver, lung, and kidney. Antiserum prepared against a synthetic pentadecapeptide corresponding to the deduced carboxyl terminus of GL2 alpha specifically reacted with a 40-kDa protein in mouse liver, brain, lung, heart, kidney, and spleen. The amount of the 40-kDa protein was highest in brain and lung. We suggest that GL1 alpha and GL2 alpha are new members of a subfamily of pertussis toxin-insensitive G-proteins.     

Collagen-induced arthritis in mice. Relationship of collagen-specific and total IgE synthesis to disease.

The relationship between production of IgE and collagen-induced arthritis in mice was examined. Collagen-specific IgE was produced as a consequence of immunization of DBA/1 mice with chicken type II collagen emulsified in CFA. We observed a rise in collagen-specific IgE antibody levels at the onset of CIA clinical and histologic signs in DBA/1 mice. This rise in IgE paralleled that of IgG2a anticollagen antibodies, an isotype implicated in the pathogenesis of CIA by other laboratories. The collagen-specific IgE contained in the plasma of mice with CIA could arm basophils for Ag- (collagen) dependent degranulation. Collagen-specific IgE may thus contribute to CIA by promoting mast cell degranulation in the synovia of susceptible mice immunized with chick type II collagen; but, further work is required to establish such a role for IgE in CIA. However, genetic differences in disease susceptibility could not be accounted for by quantitative differences in collagen-specific IgE production. Further, comparable levels of IgE anticollagen antibodies were observed in animals with active CIA and after spontaneous remission, thereby confirming that the presence of such antibodies is insufficient for disease. Total IgE levels peaked just before spontaneous remission indicating active production of IL-4. IL-4 was administered to animals with CIA to determine if this lymphokine could be involved in the remission process. IL-4 facilitated remission of CIA. Enhanced total IgE production may thus be a marker for activation of Th2 cells that produce lymphokines such as IL-4 and IL-10, factors that may be involved in the spontaneous remission process.     

Kinetics of growth and lactic acid production in continuous and batch culture

Summary In a lactic acid fermentation by Streptococcus faecalis, the specific consumption rate of glucose (v) and the specific production rate of lactic acid () were represented by the following simple equations as functions of the specific growth rate (): 1/=(1/) + 1/ = (1/) + By use of data from a batch culture, these two equations were derived from enzyme kinetics of the product inhibition. These equations were successfully applied to the results of batch culture and chemostat culture. In addition, calculation of ATP yield by these equations agreed with the experimental results better than the conventional Leudeking-Piret type equation, which includes two terms associated with growth and not with growth. Correspondence to: H. Ohara     

Contact guidance in vitro : A light, transmission, and scanning electron microscopic study

Contact guidance was studied in cultures of chick heart fibroblasts and kidney epithelium by observing the relation of these cells to fine grooves ruled in plastic culture dishes, and also to ridges or grooves in plastic replicas moulded from rulings made in metal. The relation of the cells to the regularly arranged collagen fibers of fish scales was also studied by scanning and transmission electron microscopy (SEM and TEM). On the rulings with groove periodicity in the range of 5 μm about 75% of the cells were aligned, but on grooves separated about 30 μm only 60% of cells were aligned. Cytoplasmic components of the cells such as microfilaments maintained a constant relation to the axis of the cell as a whole, but they, and also any cytoplasmic extensions, such as filopodia, bore no consistent relation to any features of the substratum, whether or not the cells were aligned. The cells were not guided to become aligned by filopodia or lamellipodia. The most remarkable and consistent finding was that cells bridged over grooves without contacting their surfaces, whether the grooves were 2 or 10 μm wide. The bridging was a characteristic of cells growing on any of the substrates, including those with grooves or ridges, and also of collagen substrates made from fish scales. A hypothesis is proposed to explain the contact guidance seen on ridged or grooved substrata and on the orientated collagen fibers involving the observed cell bridging and the fact that linear cell-to-substrate contacts (focal contacts) are known to be vital for cell movement. The cell is considered to be stiff so that as it bridges over much of the substratum there is only a limited area available for contact. Assuming that focal contacts need to be of a certain length to provide adhesion, a cell orientation that presents the maximum linear contact would be favoured. An examination of the results of this study and of the reports in the literature shows that cells on these types of substrata take on an orientation such that linear contacts would be expected to predominate.     

Thermoregulatory responses to heat and exercise in Japanese and Caucasians

Responses to heat and exercise were studied in 9 male Japanese subjects who walked on a treadmill at a speed of 4.4 – 4.8 km/h at 0 grade for 2 hours in a climatic chamber in July 1973, in Nagoya Japan. The results were compared with those obtained in a similar study made in July 1966 in Cincinnati, Ohio. The following results were obtained: (1) Japanese showed a 1.8 times higher rate of sweating than Caucasians. Total sweat from the whole body during 2 hours walk was also higher in Japanese. (2) Japanese exhibited lower chloride concentration in local sweat than Caucasians in spite of their higher dietary salt intake, higher serum chloride concentration and higher rate of sweating. While in Caucasians the sweat chloride concentration showed a tendency to continue to rise during the later period of the walk in spite of decreasing sweat rate after sweat suppression occurred, in Japanese it tended to fall in parallel with the sweat rate. No difference was observed in the length of the latent time of sweat suppression. (3) There were no differences in rectal temperature or heart rate, both at the period of equilibrium rectal temperature and at the end of the walk. (4) Mean skin temperature during the walk was significantly higher in Japanese than in Caucasians. It was concluded that the Japanese group was better heat acclimatized than Caucasians, though the two groups were considered to have been naturally heat exposed by season to the same extent.     

Rare occurrence of the tetratype tetrads in Saccharomycodes ludwigii.

Genetic data suggesting the absence of crossover in Saccharomycodes ludwigii have been described. Tetrad data obtained from 888 asci from 60 pairs of genes with 22 genetic markers showed the absence of tetratype asci, except for 5 asci in which a single pair of alleles showed tetratype segregation to the other genetic markers in each ascus. Spore arrays in the linear asci showed that the + - + - and + - - + (or - + + -) asci occurred at almost equal frequencies. The two coherent spores at each end of an ascus were always marked with different alleles of a gene.