The mechanism underlying the regulation of work-related behaviors in the monomorphic ant, Myrmica kotokui

The mechanism underlying the regulation of the work performed by the members of a colony is a crucial factor in the colonial life of eusocial organisms. If the response thresholds of the workers vary, greater-than-chance variation in the prevalence of work-related behaviors (i.e., in the “working degree”) is expected, and the distribution of these behaviors should be reestablished after demographic changes. We show that greater-than-chance variation in the working degree is restored after a demographic change in the ant Myrmica kotokui. The working degree varied markedly among workers, and the degree of variation could not be explained by chance alone. Moreover, the degree of variation could not be attributed to intrinsic factors such as reproductive potential or age. After a demographic change, some previously inactive workers started to work, whereas some previously active workers became inactive. These shifts resulted in the restoration of a substantial amount of variation in the working degree. These observations all support the hypothesis that variance in the response threshold is the basis of the regulation of work-related behaviors in this ant.     

Interstitial-tissue localization of high-molecular-weight kininogen in guinea-pig skin

A rabbit antibody against the light-chain of guinea-pig high-molecular-weight (HMW) kininogen, which was specific to HWM kininogen and did not recognize low-molecular-weight kininogen, was prepared. This antibody demonstrated the presence of HMW kininogen antigen at the interstitial-tissue space in the guinea-pig skin by means of immunohistochemistry. The interstitial-tissue HMW kininogen antigen was extracted from the skin. This antigen molecule in the skin extract behaved identically as HWM kininogen of plasma in slab-polyacrylamide gel electrophoresis under the presence of sodium dodecyl sulfate followed by immunoblotting. Therefore, it was concluded that HMW kininogen was present in the interstitial-tissue fluid in the skin. The amount of HMW kininogen in the skin extract was quantified by a sandwich enzyme-linked immunosorbent assay with the anti-light-chain antibody and a goat anti-guinea-pig HMW kininogen antibody. On the assumption that the interstitial-tissue volume is 50 ml/100 g wet skin tissue, the average concentration of HMW kininogen in the interstitial-tissue fluid of the skin was calculated to be 23% of the plasma concentration. On the other hand, the proportion of intravascular HMW kininogen (derived from blood remaining in the vessels of the harvested skin) in relation to the total HMW kininogen in the skin extract was quantified by measuring the radio-labelled HMW kininogen which had been injected intravenously as a tracer of the intravascular HMW kininogen. About 5% of the total HMW kininogen in the skin extract was calculated to be derived from the intravascular blood volume of the skin, indicating that the majority of the HMW kininogen in the skin extract was derived from the extravascular-tissue space.     

Intraannual and interannual changes in the surface area of a closed lake complex in southwestern Siberia using NOAA images

The Lake Chany complex, located in southwestern Siberia, consists of large shallow lakes with an average depth of about 2.2m. The area of the lake fluctuates with the water level, which is closely related to the amount of inflow and evaporation, as the lake complex is endorheic. Using National Oceanic and Atmospheric Administration (NOAA) satellite images of the ice-free periods from 1999 to 2004, we evaluated the seasonal changes in the lake area and surrounding vegetation of the Lake Chany complex. The maximum lake area was observed in early May and decreased until late July. The lake area in August was about 60% of the maximum. Subsequently, the area tended to increase until early October. Compared to ground-truth data, the areas undergoing seasonal fluctuations in the NOAA images corresponded to vast stands of vegetation (Phragmites australis) that were several kilometers wide. These areas seem to be influenced by the inflow of snow-melt water and reed growth. Although interannual differences in the seasonal change in lake area were not great for the whole lake complex, the isolated Yudinskii Pool showed large interannual differences during summer and autumn, suggesting that monitoring this area using NOAA images will be useful for estimating the interannual fluctuations in the southwestern Siberian environment.     

Kinetic study on the dimer-tetramer interconversion of phosphorylase b by a stopped-flow X-ray scattering method

The dimer-tetramer interconversion of phosphorylase b induced by the binding of AMP and Mg2+ was monitored using a stopped-flow X-ray scattering method. The rate constants of this second-order reaction have been determined by a nonlinear least-squares method. Burst phases in both radii of gyration and zero-angle intensities were detected at the initial step of the reaction. This suggests that rapid association might take place, followed by a slow association process of which the kinetics were measured in the present study. The radius of gyration of tetrameric phosphorylase b was determined and found to be in excellent agreement with that of phosphorylase a, but different from that of phosphorylase b reported elsewhere (G. Puchwein, O. Kratky, C. F. Golker and E. Helmreich, Biochemistry 9 (1970) 4691). The reason for this inconsistency is discussed.     

Biological activities of mouse haptoglobin elicited by administration of an antitumor polysaccharide,PSK

The concentration of mouse haptoglobin in serum was increased by administration of an antitumor polysaccharide, PSK. The administration of the purified mouse haptoglobin inhibited the growth of Sarcoma-180 cells implanted in ICR mice. Furthermore, this glycoprotein enhanced macrophage activitiesin vitro, as judged from the cytostatic and cytolytic activities, glycose consumption, O₂-production, and interleukin-1 production of macrophages. In addition, mouse haptoglobin enhanced the cytolytic effect of cytotoxic T-lymphocytes. These results suggested that haptoglobin has a role in restoring or enhancing the resistance of the host against tumors.Abbreviations FCS fetal calf serum - LPS lipopolysaccharide - CTL cytotoxic T-lymphocytes - IL-1 interleukin 1 Part of this work has been presented at the 14th International Congress of Chemotherapy, Kyoto, Japan, June, 1985.     

Application of a new method of antibody-enzyme conjugation with maleimide derivative for immunohistochemistry: hepatocellular production, interstitial tissue distribution, and renal cell reabsorption of plasma albumin in guinea pig

A new sophisticated method for enzyme-antibody conjugation developed in quantitative solid-phase enzyme immunoassay was revealed to be an applicable method for immunohistochemistry; one that offered several advantages over present methods. Using a new maleimide derivative as a coupling reagent, monomeric conjugate of horseradish peroxidase and Fab' antibody was easily prepared with high efficiency and reproducibility. Nonspecific staining was greatly reduced in the presence of this monomeric conjugate. Since the enzyme activity and antigen-binding activity were well preserved in the conjugate, the reaction was strong enough to analyze the antigen localization in intracellular organelles or in interstitial tissue space by both light and electron microscopy. The fate of plasma albumin was investigated in liver, skin, and kidney using the new method with rabbit anti-guinea pig albumin antibody, and satisfactory results were obtained. In the liver, the reaction products were observed in the rough and smooth endoplasmic reticulum and the Golgi apparatus in hepatocytes, which confirmed the synthesis of plasma albumin in hepatocytes of guinea pig. In a study of the distribution of albumin, reaction products were seen in the intercellular space of the epidermis, along the basement membranes of epidermis and of proximal convoluted tubules in kidney, and among the collagen fibers in interstitial tissue, particularly at papillary dermis, suggesting the wide distribution of plasma albumin in interstitial extravascular tissue spaces. In addition, positive reaction was obtained in the apical vesicles and the lysosomes of the proximal convoluted tubules and in the pinocytotic vesicles of the basal cells of epidermis, suggesting the reabsorption and destruction of albumin in the kidney and the skin.