Resistance of thermophilic ATPase (TF1) to specific F1-atpase inhibitors including local anesthetics

F1-ATPase obtained from mesophilic organisms is inhibited by specific inhibitors, such as aurovertin, efrapeptin, quercetin and several local anesthetics. This property has been explained by the common structure at the catalytic center of F1. However thermophilic F1 (TF1), which has the same primary structure at the center as other F1's, was shown to be resistant to these F1-specific inhibitors. Thus, the inhibitory mechanism may be explained not by the common structure at the catalytic site, but by some conformational changes of the flexible mesophilic F1 molecules or the absence of an inhibitor binding site in thermophilic F1.     

Coexistence of cardiac-type and fast skeletal-type myosin light chains in embryonic chicken cardiac muscle

Myosin from embryonic chicken ventricle contained a light chain component which comigrated with fast skeletal myosin light chain 1 (Lf1) on two dimensional electrophoresis in addition to cardiac type light chains (Lc1 and Lc2). Immunoblot analysis showed that this minor light chain band reacted with anti-Lf1 antibody. Antigens binding with anti-Lc1 and anti-Lf1 antibodies were located on myofibrils in embryonic cardiac muscle cells in vivo and in vitro. From these observations, we conclude that a small amount of Lf1 exists in embryonic chicken cardiac muscle.     

The effect of 2-deoxy-D-glucose on insulin release by neonatal rat B cells in culture

The culture for 7 days in medium with 5.5 mM glucose and 1 mM 2-deoxy-D-glucose enhanced the glucose sensitivity of neonatal rat B cells, and even stimulated their growth in vitro. Also, 2-deoxy-D-glucose supplementation maintained insulin release evoked by leucine and 2-ketoisocaproate from B cells at day 7 at levels several times higher than at day 1. The effect of leucine was greatly augmented by glutamine, whereas that of the 2-keto acid remained almost unchanged irrespective of the presence of glutamine. These results suggest an increase in oxidative catabolism of medium nutrients in B cells grown in medium with 2-deoxy-D-glucose for 7 days, and such metabolic changes may promote the growth of B cells in vitro.     

Histochemical demonstration of asparagine-linked oligosaccharides in glycoproteins of human placenta and umbilical cord tissues by means of almond glycopeptidase digestion

Almond glycopeptidase is an enzyme which cleaves specifically beta-aspartylglucosylamine linkages in glycoproteins with asialo-carbohydrate moieties. With this enzyme, it was possible to demonstrate the localization of asparagine-linked oligosaccharides in glycoproteins of human placenta and umbilical cord tissues. In these tissues, the oligosaccharides were shown to react positively for a series of histochemical procedures for neutral complex carbohydrates such as periodic acid-Schiff (PAS), peroxidase-labelled Ricinus communis agglutinin-I-diaminobenzidine (PO-RCA-DAB) and concanavalin A-peroxidase-diaminobenzidine (Con A-PO-DAB). The asparagine-linked carbohydrates were localized in the placental villi, blood vessels and perivascular tissues and the umbilical cord blood vessels and matrix. The results of previous biochemical analyses performed upon the same tissues (Takahashi et al., 1981) have corroborated the results of the histochemical studies. The present results appear to substantiate the usefulness of almond glycopeptidase for the histochemical demonstration of the particular oligosaccharides of glycoproteins in tissues in general.     

13C- and 1H-nmr evidence for all-cis peptide bonds in cyclic tetrapeptide cyclo(L-Pro-Sar)2

Conformations of the cyclic tetrapeptide cyclo(L -Pro-Sar)₂ in solution were studied by ¹H- and ¹³C-nmr spectrometry and model building. The nmr data provide definite evidence that this cyclic peptide exists chiefly in two conformations, namely, a C₂-symmetric conformation and an asymmetric structure. The former was demonstrated to be predominant in polar solvents (100% in Me₂SO-d₆). This structure contains all cis-peptide bond linkages and all trans′ Pro C^α?CO bonds. It represents the first cyclic tetrapeptide in which all four peptide bonds have been found in the cis-conformation. As the polarity of the solvent decreases, the population of C₂-symmetric conformers decreases (88% in CD₃CN and 65% in CDCl₃). At the same time, a minor asymmetric conformer, characterized by cis-cis-cis-trans peptide bond sequences (two cis Sar-Pro bonds, one cis Pro-Sar bond, and one trans Pro-Sar bond), is seen to increase (9% in CD₃CN and 30% in CDCl₃). A proposed predominant conformation in solution for cyclo(L -Pro-Sar)₂ was compared with a crystal structure, as reported in an accompanying paper. Both structures show striking overall similarities.     

Co-operative dynamics in organelles

Some organelles produce elementary life phenomena which are characterized by the spontaneous formation and/or maintenance of ordered macroscopic dynamics like e.g. the shortening of sarcomeres in striated muscle and the transmission of electrical impulses in an axon. It has been widely accepted that such organelles are organized molecular systems where molecular elements work independently under constraint of a more or less rigid and regular structure of the system. On the other hand, such organelles should be regarded as self-organizing systems if the ordered macroscopic dynamics are self-organized. As the macroscopic dynamics gradually emerge, the microscopic dynamics of its elements become linked to each other through a feedback loop. It is crucial for the feedback loop to operate that the macroscopic dynamics are "free" in their behavior. In the present paper, it is pointed out that the traditional view of independent molecular elements has been obtained from experiments in which, by means of external constraint, the macroscopic dynamics is "clamped". Under such conditions, the self-organizing system may behave as an organized one. Based on synergetics we propose criterions for proving self-organizing systems, and, by applying the criterions, we conclude that skeletal muscle actomysin is a co-operative element in the sense of self-organization.     

Characteristics of the estrous cycle of the swamp buffalo under temperate conditions

Estrous cycle, duration of estrus and time of ovulation of eight cyclic buffaloes were examined during a period of one year. Animals were kept under loose-housing conditions and fed according to the Japanese Feeding Standards for dairy cattle. All the animals were observed for the occurrence of estrus twice daily by using a vasectomized bull, and ovarian cycles of each animal were monitored by weekly rectal palpation. Duration of estrus and time of ovulation were determined in 32 estrous periods from eight animals. Animals came in estrus throughout the year. The estrous cycles corresponding to single ovarian cycles ranged from 11 to 38 days with a mode interval of 20 days, averaged 21.5 +/- 4.7 days. Percentage of the cycles within a range of a mean +/- 1 SD (17-26 days) was 79.2 %, whereas that of cycles shorter or longer than the expected range was 9.4 % and 11.4 %, respectively. Estrus took place regardless of the time of day and lasted 9 to 27 hr (19.9 +/- 4.4 hr). Ovulation occurred 6 to 21 hr (13.9 +/- 3.4 hr) after the end of estrus, with a mode interval of 12 hr. There were no significant seasonal variations in the estrus characteristics studied.     

Mapping of the human gene for epidermal growth factor receptor (EGFR) on the p13 leads to q22 region of chromosome 7

We previously reported that the structural gene for epidermal growth factor receptor (EGFR) can be mapped to the p22 leads to qter region of human chromosome 7 (Shimizu et al., 1979, 1980). In the present study, we produced two series of human-mouse cell hybrids by fusing mouse A9 cells that are deficient in EGFR with the human diploid fibroblast lines GM1356, 46,XX,t(1;7)(p34;p13), and GM2068, 46,XX,t(6;7)(q27;q22), both of which possess EGF receptors. Expression of EGF binding ability in the former series of cell hybrids was correlated with the retention of the human translocation chromosome containing the 7p13 leads to qter region, and in the latter series of cell hybrid it was correlated with the retention of the human translocation chromosome containing the 7pter leads to q22 region. Therefore, the EGFR gene can be localized in the p13 leads to q22 region of chromosome 7.