A growth-promoting factor existing on the body surface of rats

Effects of water-soluble matter adhering to rat hairs on fibroblasts were examined. The dialysate of the wash water of rat hairs significantly enhanced the cell proliferation of both diploid human dermal fibroblasts (DHDF) and diploid rat fibroblasts (DRDF). The cell growth-promoting activity was partially purified by a gel filtration column chromatography. The activity permeates through a ultrafiltration membrane (M.W. cut off: 500). Analyses of its chemical nature show that it is soluble in water, dimethyl sulfoxide or acetonitrile, insoluble in other organic solvents examined, stable to heat or pH shock, and resistant to a bacterial protease.     

Synchronous division and the pattern of diel vertical migration of Heterosigma akashiwo (Hada) Hada (Raphidophyceae) in a laboratory culture tank

Heterosigma akashiwo (Hada) Hada (Raphidophyceae) causes red tides in Osaka Bay (Japan). A clonal culture of the alga was grown in a 2 m tall culture tank on a 12: 12 LD cycle to determine patterns of vertical migration and cell division. A specific growth rate of 0.43 ln unit · day⁻¹ was obtained during complete mixing conditions. Under weakly stratified conditions (≈ΔT = 3–4°C/1.5 m), H. akashiwo in the tank grew and showed a similar pattern of vertical migration to that observed in the field for at least 6 days. Cell concentration, mean cell volume, and photosynthetic capacity, estimated by DCMU-induced fluorescence increase of H. akashiwo, were monitored in the stratified tank at 2-h intervals over 24 h at three levels in the water column. Cell ascent began shortly before the light period and vertically swimming cells were smaller in size than those sampled near the bottom of the tank. The cell division cycle and the pattern of vertical migration were phased individually by the light regime and were well synchronized with each other. This synchrony must be due to the interrelation between these two processes or the existence of a clock which controlled endogenous rhythms of both processes and was entrained by a light: dark cycle. The relative increase of fluorescence with DCMU was higher for migrating cells than for non-migrating cells.     

Use of a copper-phthalocyanine membrane electrode for rapid preliminary detection of polycyclic mutagens

Preliminary screening of polycyclic mutagens is achieved within 20 min by using a biomimetic electrode composed of an oxygen electrode and a copper-phthalocyanine membrane. When benzo[alpha]pyrene (0.05 mM) was added to the buffer solution in the presence of 0.98 M hydrogen peroxide, the current of the phthalocyanine electrode decreased. A linear relationship was obtained between the current decrease and the benzo[alpha]pyrene concentration over the range 0.19-0.60 mM. The minimum measurable concentration for benzo[alpha]pyrene was 0.01 mM. Such responses were not obtained for other organic compounds such as alcohol, ether, n-hexane and cyclohexane. The copper-phthalocyanine membrane electrode has selectively detected polycyclic mutagens such as amino acid pyrolysis products. The current decrease was 1.18-1.46 microA when 0.05 mM amino acid pyrolysis products were employed.     

Level of translatable messenger RNA coding for argininosuccinate synthetase in the liver of the patients with quantitative-type citrullinemia

Summary The translation activity of mRNA coding for argininosuccinate synthetase in total RNA extracted from the liver of three patients with quantitative-type citrullinemia was determined using a cell-free translation system. In two patients, the hepatic content of the enzyme was about 20% of the control value, whereas translatable mRNA level for the enzyme was similar to or slightly lower than those of control livers. In the third patient, the enzyme content was about 50% of the control value, and mRNA activity for the enzyme was low normal. These results indicate that at least in the first two patients, the decrease in the enzyme protein is due either to increased degradation of the enzyme or to decreased translation in the patient's liver.     

Induction of the acrosome reaction in goat spermatozoa in simple physiological salt solution

The present study was carried out to determine whether K+, Mg2+, PO4(3-), and HCO3- in a medium are necessary for inducing the acrosome reaction in ejaculated goat spermatozoa. Washed goat spermatozoa were resuspended in K-1 medium, containing NaCl, KCl, CaCl2, MgCl2, NaH2PO4, and NaHCO3; in K-2 medium, containing NaCl, CaCl2, NaH2PO4, and NaHCO3; in K-3 medium, containing NaCl, CaCl2, and NaHCO3; and in K-4 medium, containing only NaCl and CaCl2, followed by preincubation in a sealed glass tube at 39.5 degrees C for 1, 2, or 3 h. The sperm acrosome reaction was evaluated by the trypan blue-Giemsa method and hamster test. The results were essentially the same in all cases. Following preincubation for 1 h, however, the percentage of acrosome-reacted spermatozoa, the proportion of zona-free hamster eggs penetrated by spermatozoa, and the average number of spermatozoa in the vitellus of these penetrated eggs were low; all values indicated a significant increase with preincubation for 2 and 3 h. The presence of K+, Mg2+, PO4(3-), and HCO3- in the medium thus does not appear necessary for inducing the acrosome reaction in goat spermatozoa, since they can undergo the reaction during preincubation in a simple physiological salt solution containing only NaCl and CaCl2 when preincubated in sealed glass tubes at 39.5 degrees C.     

Concentrations of essential elements after repeated administrations of tin and selenium

To study effects of simultaneous administration of tin (Sn) and selenium (Se) on concentrations of several essential elements, mice were injected with either SnCl2 (ip) or Na2SeO3 (sc), alone or both compounds at a daily dose of 5 mumol/kg each for 12 consecutive days. Mice were sacrificed at 20 h after the last injection and concentrations of Sn, Se, Na, Ca, Zn, P, Fe, K, and Mg in the liver, kidney, spleen, pancreas, testis, seminal vesicle, lung, femoral muscle, and femoral bone were determined. In the control mice, Sn and Se concentrations were the highest in bone (0.69 micrograms Sn and 6.93 micrograms Se/g dry wt). Administered Sn was found to accumulate in all organs except the testis. Among the essential elements determined, Na was the most affected in terms of concentration in the organs and Mg was the least affected element in these organs. Among the organs tested, each elemental concentration in the pancreas was most affected. Simultaneous injections of Sn and Se appeared to keep the correlation coefficients between elements similar to those found in the control mice.     

Regulation by Androgen of Levels of the β Subunit of Nerve Growth Factor and Its mRNA in Selected Regions of the Mouse Brain

Abstract: Our previous studies showed that the concentration of the β subunit of nerve growth factor (β-NGF) in nervous tissues is higher in male than in female mice. To identify the brain regions that are affected by androgens, the amounts of β-NGF protein and its mRNAs were measured in male, female, and castrated male CD-1 mice and testicular feminization mice at 3–4 months of age. Among tissues examined, the hypophysis of males contained the highest average concentration of β-NGF protein. In most regions of the brain, individual levels were more variable in males than in females. However, after the castration, such variations in β-NGF levels disappeared. Average levels of β-NGF protein in males were higher in the cerebellum (eightfold higher), olfactory bulb (12-fold higher), hypothalamus (sixfold higher), and hypophysis (72-fold higher) than thope in corresponding regions of females. No significant differences were observed in levels of β-NGF protein in the hippocampus, cerebral cortex, striatum, septum, and brainstem. The castration of male mice caused a reduction in levels of β-NGF protein in the hypothalamus and hypophysis, but not in the cerebellum and olfactory bulb, to the femgle levels. The concentrations of β-NGF protein in testicular feminization mice were similar to those in female CD-1 mice in all regions. The concentrations of mRNA for β-NGF in the olfactory bulb and hypophysis from males were higher than those from females. By contrast, northern blots showed no remarkable differences in the amounts of brain-derived neurotrophic factor and neurotrophin-3 between the two sexes. Thus, in some regions of the brain, the production of β-NGF appears to be regulated by testosterone, but the regulatory mechanisms do not appear to be simple. Our present results indicate that the binding of testosterone to its receptor is an important step in the regulation of the level of β-NGF in these region.     

Genetic Transformation in Helicobacter pylori

Genetic transformation in Helicobacter pylori was investigated by using its chromosomal and plasmid DNAs. Six out of the eight strains exhibited the natural competence for incorporation of H. pylori chromosomal DNA, and all the strains incorporated the donor DNA efficiently by washing and concentrating the cells, with a glycerol solution. The much higher frequency of transformation was obtained in each strain by means of electroporation. Electroporation experiments were also conducted by use of the recombinant DNAs consisting of the H. pylori and Escherichia coli plasmids as the donors, and the occurrence of the homologous recombination was demonstrated between the incoming H. pylori plasmid-derived region and the corresponding region of the originally residing plasmid in H. pylori.     

DIEL CHANGES IN THE COMPOSITION OF PHOTOSYNTHETIC PIGMENTS AND CELLULAR CARBON AND NITROGEN IN CHATTONELLA ANTIQUA (RAPHIDOPHYCEAE)1

An axenic clonal culture of Chattonella antiqua (Hada) Ono was grown on a 12: 12 h LD cycle in a laboratory culture tank containing 1 m³ of f/2 medium. Diel changes in mean cell volume, cellular carbon (carbon content per cell), C/N ratio, cellular Chl a, Chl a/c ratio and carotenoid composition were observed. Mean cell volume and cellular C, N and pigments increased during the light period as a result of photosynthesis and decreased with increase of cell concentration by phased cell division during the dark period. These changes indicated that carbon assimilation and pigment synthesis occurred together during the light period. However, the patterns of increase were not the same since different diel patterns were also found in the ratios of C/N and chl a/c. Photosynthetic pigments were analyzed by reversed-phase high-performance liquid chromatography with ion-pairing solution. This analysis showed that the dominant carotenoids in C. antiqua were fucoxanthin, violaxanthin and β-carotene. Diel patterns of Chls a and c were similar to that of fucoxanthin but different from those of violaxanthin and β-carotene. The cellular contents of Chl a, fucoxanthin and carbon increased in a parallel manner during the light period. On the other hand, the increase of violaxanthin was restricted to only a few hours at the beginning of the light period during cell division cycles.