Phosphoprotein phosphatase inhibits flagellar movement of Triton models of sea urchin spermatozoa

Phosphoprotein phosphatase prepared from bovine cardiac muscle was used to study the roles of axonemal phosphoproteins in the flagellar motility of sea urchin spermatozoa. When isolated axonemes were incubated with cyclic AMP-dependent protein kinase, gamma-[32P]ATP and cyclic AMP, more than 15 polypeptides were phosphorylated. Most were dephosphorylated by treatment with phosphoprotein phosphatase. When Triton models of sea urchin spermatozoa were treated with phosphoprotein phosphatase followed by an addition of ATP, the flagellar motility of the models was drastically reduced in comparison with that of the untreated models. The motility of the phosphatase-treated Triton models was partially restored by an addition of cyclic AMP and cyclic AMP-dependent protein kinase. These data give strong support to the idea that the motility of eukaryotic flagella is controlled by a protein phosphorylation-dephosphorylation system.     

Serum and tissue coenzyme Q9 in rats with thyroid dysfunctions

Serum and tissue CoQ9 levels were determined in hypothyroid, euthyroid and hyperthyroid rats. A significant negative correlation was demonstrated between serum FT4 or T3 and CoQ9 in rats with various states of thyroid functions. Liver CoQ9 was significantly increased in rats rendered mildly hyperthyroid. There was a significant positive correlation between serum FT4 or T3 and liver CoQ9. While liver CoQ9 did not significantly change in severely hyperthyroid animals, liver mitochondrial CoQ9 showed a significant positive correlation with serum T3. Kidney and heart CoQ9 levels did not significantly change in hyperthyroid rats, but those in hypothyroid rats showed a tendency to increase. It was suggested that the synthesis of CoQ9 was increased in the liver in hyperthyroidism.     

Changes of aldolase A and B messenger RNA levels in rat liver during azo-dye-induced hepatocarcinogenesis

The expression of aldolase A and B mRNAs during azo-dye-induced carcinogenesis in rat liver was examined. After feeding the dye for 18 weeks, the level of aldolase A mRNA increased to about 11 times that in a normal liver, with the concomitant decrease of aldolase B mRNA level to about 25% of that in a normal liver. These changes did not occur progressively during the carcinogenesis, but occurred as an additional phase after 4 week-feeding of the azo-dye. At this stage, the levels of aldolase A and B mRNAs were about 7 times and 45% of that in a normal liver, respectively. This biphasic pattern in the aldolase isozyme expression in the azo-dye-fed rat liver is discussed together with the kinetic data of the enzyme activity.     

New affinity adsorbents containing deoxycytidine, deoxyadenosine, or deoxyguanosine and their interactions with deoxynucleoside-metabolizing enzymes

3'-(4-Aminophenyl phosphate) derivatives of deoxycytidine (dCyd), deoxyadenosine (dAdo), and deoxyguanosine ( dGuo ) were synthesized. The inhibitory effects of these compounds on mammalian and bacterial deoxynucleoside kinases and several other deoxynucleoside-metabolizing enzymes were examined. The same derivatives were coupled to carboxyl-terminal Sepharose CL-6B (3-8 mumol of ligand/mL of gel), and each of the resulting affinity adsorbents was tested with various partially purified enzymes. Reasonable correlation between the inhibitory effect of a soluble deoxynucleoside 3'-phosphate diester and affinity of the corresponding Sepharose adsorbent for the enzyme was observed. Among the three dCyd kinases examined, only the bovine mitochondrial enzyme was adsorbed onto the dCyd-Sepharose column and eluted biospecifically by 1 mM dCyd (1400-fold purification). Its Ki toward the dCyd derivative was relatively low (1.1 mM), whereas no measurable inhibition was seen with mammalian cytosol or bacterial enzymes that did not stick to the column. The Ki of the dAdo derivative toward three dAdo kinases was more than 5 mM in each case, and none of these were retained by dAdo-Sepharose. Among the other dAdo-metabolizing enzymes examined, nucleoside phosphotransferase from barley (Ki = 1.2 mM) was adsorbed to dAdo-Sepharose at pH 5.0 and was biospecifically eluted with dAdo or AMP after suppressing ionic binding by adjusting the pH to 6.0 (480-fold purification to homogeneity). Mammalian mitochondrial dGuo kinase (beef liver) showed the lowest Ki (0.16 mM) among the enzymes tested and was biospecifically purified with dGuo -Sepharose (2800-fold purification).(ABSTRACT TRUNCATED AT 250 WORDS)     

Brain insulin binding is decreased in Wistar Kyoto rats carrying the 'fa' gene

We have previously reported that insulin binding is decreased in the olfactory bulb of both heterozygous (Fa/fa) and obese (fa/fa) Zucker rats. In the present study, we measured insulin binding in membranes prepared from the olfactory bulb, cerebral cortex, and hypothalamus of control (Fa/Fa) Wistar Kyoto rats; "fatty" (fa/fa) Wistar Kyoto rats; and phenotypically lean (Fa/?) Wistar Kyoto rats. Insulin binding was decreased in all brain regions, as well as the liver of the obese Wistar Kyoto fa/fa rats. Additionally, insulin binding was decreased in the liver and brain membranes from the Fa/? Wistar Kyoto rats. As most of the Fa/? rats were probably carriers of one 'fa' gene, but the population was only slightly hyperinsulinemic, we conclude that--as in the Zucker rat--it is the presence and expression of the 'fa' gene rather than downregulation which results in the decreased insulin binding. Thus, regulation of the brain insulin receptor appears to be independent of plasma or cerebrospinal fluid insulin levels.     

Conversion of 4-aminobutyraldehyde to γ-aminobutyric acid in striatum treated with semicarbazide and kainic acid

4-Aminobutyraldehyde (ABAL) has been shown to cross the blood-brain barrier and to be converted rapidly to -aminobutyric acid (GABA) in various regions of the brain. In this paper, the formation of GABA from ABAL was studied with striatum that had suffered a lesion to GABA synthesis via glutamic acid decarboxylase (GAD). The GABA formation from ABAL was invariably observed in striatum in which GAD was severely inhibited by semicarbazide or kainic acid. Thus, this is another pathway for GABA formation.     

Regulation of sperm flagellar movement by protein phosphorylation and dephosphorylation

Flagellar motility of Triton models of sea urchin spermatozoa was reactivated by cyclic AMP-dependent protein kinase and a protein factor, termed motility activator, both of which were prepared from the detergent-extract of sea urchin spermatozoa. It was shown that phosphorylation of the motility activator by the protein kinase is necessary for the reactivation of flagellar motility [Ishiguro et al, J. Cell Biol. 92:777-782, 1982; Murofushi et al, in "Biological Functions of Microtubules and Related Structures," Academic Press, 1982]. Reactivating factor was also detected in a KCl-extract of the axoneme fraction devoid of the detergent-extractable materials. The activity of this factor was also cyclic AMP- and protein kinase-dependent. Furthermore, when freshly prepared Triton models were treated with phosphoprotein phosphatase prepared from bovine cardiac muscle, the flagellar motility was drastically suppressed. This inhibition of the motility was partially recovered by the addition of cyclic AMP and protein kinase to the phosphatase-treated models.     

Cycling of soil carbon in a Japanese red pine forest II. Changes occurring in the first year after a clear-felling

Cycling of soil carbon in the first year after a clear-felling was compared with that before the felling in a Japanese red pine forest in Hiroshima Prefecture, west Japan. The daily mean temperature at the soil surface in summer was increased after the felling in comparison to that before felling, and the water content of both the A₀ layer and the surface mineral soil was decreased due to the loss of the forest canopy. The rate of weight loss of the A₀ layer was reduced after felling. However, accumulation of the A₀ layer rapidly decreased because of the lack of litter supply to the forest floor. Low soil respiration after felling was mainly caused by the cessation of root respiration. Analysis of annual soil carbon cycling was then conducted using a compartment model. The relative decomposition rate of the A₀ layer decreased whereas that of humus and dead roots in mineral soil increased to some extent after felling. The accumulation of carbon in mineral soil, however, increased slightly due to the supply of humus from roots killed by the felling.     

Structure and affinities of the petrified plants from the cretaceous of Northern Japan and Saghalien III petrified plants from the upper cretaceous of Saghalien

Five species including two new species,Araucarioxylon kiiense Ogura,Taxodioxylon albertense (Penhal.) Shimakura,Cupressinoxylon cryptomerioides Stopes,Xenoxylon watarianum sp. nov. andCedroxylon shimakurae sp. nov., were described from the Upper Cretaceous (Late Turonian-Santonian) of southern Saghalien. Consecutive number from the previous paper (Nishida and Nishida, 1985). Contributions from the Laboratory of Phylogenetic Botany, Chiba University No. 100. Supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture No. 59540441.