Ecological studies on the population of isaza,Chaenogobius Isaza Tanaka,in Lake Biwa,with special reference to the effects of population density upon its growth

1. In order to get the knowledge on the age composition of “isaza” population in Lake Biwa and the effect of population density on growth, monthly distribution of mean body length and mean body weight has been analyzed on the basis of monthly haul by “isazabiki” trawl during 1949 to 1953 and also 1960 to 1965.
2. There is no apparent sex difference in the growth in the first and second years of life.
3. “Isaza” population is composed of two age groups, age 0 and 1 groups (1+fish), the latter occupying by far the greater part in commercial catch.
4. During the growth season fishes of both ages feed mainly on zooplankton, though in winter frequently take chironomid larvae, gammaridae and others in volume.
5. The growth season falls in the period from April to October in both age groups.
6. A considerable yearly variation occurring in growth is in close connection with the fluctuation of population density of all ages.
7. The influence affected by the density of age 1 group is larger than that by age 0 group.

     

Study of glomerular vasculature in teleosts with the resin-replica method

Glomerular vasculature was investigated in the carpCyprinus carpio, the scorpionfishSebastiscus marmoratus, and the marine catfishPlotosus lineatus with the resin-replica method. An afferent arteriole was connected with a glomerulus in every fish. It was slender in the carp, whereas the scorpionfish and marine catfish possessed thick afferent arterioles. The glomerular capillaries were sinusoidal. The divergences, convergences, and windings of these capillaries were not well developed in any of the fish. The glomerular capillaries converged into an efferent arteriole in the carp and scorpionfish. In the marine catfish, on the other hand, most of the glomeruli had two efferent arterioles.     

Type I protein kinase C isozyme in the visual-information-processing pathway of monkey brain

Previously using PKC isozyme-specific antibodies for immunoblot analysis, we demonstrated the heterogeneous distribution of PKC isozymes in various regions of monkey and rat brains and that type I PKC was most abundant in cerebellum, hippocampus, amygdala, and cerebral cortex (Huang et al.: J Biol Chem 262:15714-15720, 1987). Using these antibodies, we have also demonstrated that type I, II, and III PKC are products of PKC genes gamma, beta, and alpha, respectively (Huang et al.: Biochem Biophys Res Commun 149:946-952, 1987). By immunocytochemical analysis, type I PKC-specific antibody showed strong reactivity in various types of neuron in hippocampal formation, amygdala, cerebellum, and neocortex. In hippocampal formation, granule cells of dentate gyrus and pyramidal cells of hippocampus were heavily stained. By immunoblot analysis, relative levels of PKC isozymes in several areas of monkey cerebral cortex involved in the visual information processing and storage were determined. Both type II and III PKCs appeared to be evenly distributed and at moderate levels, type I PKC formed a gradient of increasing concentration rostral along the cerebral cortex of occipital to temporal and then to the limbic areas. Neurobehavioral studies have demonstrated that the neocortical and limbic areas of the anterior and medial temporal regions participate more directly than the striate, prestriate, and posterior temporal regions in the storage of visual representations and that both hippocampus and amygdala are important in the memory formation. As type I PKC is present at high levels in hippocampus, amygdala, and anterior temporal lobe, we predict that the type I protein kinase C may participate in the plastic changes important for mnemonic function.     

Heptapeptide toxin production during the batch culture of two Microcystis species (Cyanobacteria)

Changes in the content of cyclic heptapeptide hepatotoxins called microcystins were investigated during batch culture of two Microcystis species using high performance liquid chromatography. After adsorption to ODS-silica gel cartridges and elution with methanol, the toxins were analyzed and quantified by HPLC. 35 μg per 100 mg dry cells of microcystin-RR, 34 μg of -YR and 43 μg of -LR were present at the beginning of the exponential growth phase of M. viridis. Microcystin-RR increased markedly towards the end of the exponential phase with the maximum content of 112 μg per 100 mg cells was measured at the late stage of the exponential phase. A remarkable increase of microcystin-YR from 130 μg per 100 mg cells to 1020 μg was observed during the exponential phase of a highly toxic strain of M. aeruginosa. However no clear differences were found in the pattern of change among the three toxins during the growth course.     

IFN-gamma is the inducer of indoleamine 2,3-dioxygenase in allografted tumor cells undergoing rejection

The depletion of an essential amino acid, tryptophan, caused by induction of indoleamine 2,3-dioxygenase (IDO), has been shown to be a mechanism involving self-defense against inhaled microorganisms and tumor growth. We recently reported that the IDO is dramatically (approximately 50-fold) induced in allografted tumor (3-methylcholanthrene-induced ascites type tumor cells) cells undergoing rejection, and that the enzyme is induced by factor(s) released through the interaction of allografted tumor cells with infiltrating leukocytes. The culture supernatant of infiltrating leukocytes, which were harvested on day 7 after tumor transplantation, induced the highest IDO activity in the tumor cells. The inducer activity was completely neutralized by the addition of antibody to IFN-gamma but not by antibody to IFN-alpha/beta. Approximately 6 U/ml of IFN-gamma was detected by an ELISA assay in the 12-h culture supernatant with 2 x 10(6) leukocytes/ml, and rIFN-gamma at 6 U/ml induced IDO in 3-methylcholanthrene-induced ascites type tumor cells to the same extent as IFN-gamma in the culture supernatant. Moreover, i.p. administration of antibody to IFN-gamma almost completely inhibited the induction of IDO in the allografted tumor cells. These observations indicate that the factor responsible for IDO induction in the allografted tumor cells is IFN-gamma.     

Lysosomal acid lipase deficiency in rats: lipid analyses and lipase activities in liver and spleen

We report the biological characterization of an animal model of a genetic lipid storage disease analogous to human Wolman's disease. Affected rats accumulated cholesteryl esters (13.3-fold), free cholesterol (2.8-fold), and triglycerides (5.4-fold) in the liver, as well as cholesteryl esters (2.5-fold) and free cholesterol (1.33-fold) in the spleen. Triglycerides did not accumulate, and the levels actually decreased in the spleen. Analysis of the fatty acid composition of the cholesteryl esters and triglycerides showed high percentages of linoleic acid (18:2) and arachidonic acid (20:4) in both organs, especially in the liver. No accumulation of phospholipids, neutral glycosphingolipids, or gangliosides was found in the affected rats. Acid lipase activity for [14C]triolein, [14C]cholesteryl oleate, and 4-methyl-umbelliferyl oleate was deficient in both the liver and spleen of affected rats. Lipase activity at neutral pH was normal in both liver and spleen. Heterozygous rats showed intermediate utilization of these substrates in both organs at levels between those for affected rats and those for normal controls, although they did not accumulate any lipids. These data suggest that these rats represent an animal counterpart of Wolman's disease in humans.     

Close linkage of MEN2A with RBP3 locus in Japanese kindreds

Summary The gene responsible for multiple endocrine neoplasia type 2A (MEN2A) has recently been assigned to the pericentromeric region of chromsome 10 in European Caucasian kindreds by linkage analysis using a DNA marker, interstitial retinol-binding protein 3 (RBP3). We have found tight linkage between the MEN2A and RBP3 loci in Japanese MEN2A kindreds. The maximum lod score is 5.19 at a recombination fraction of 0.00. This result suggests that mutation of a certain gene close to RBP3 is responsible for MEN2A irrespective of ethnic backgrounds.     

Sulfated proteoglycans synthesized by Neuro 2a neuroblastoma cells: Comparison between cells with and without ganglioside-induced neurites

Mouse neuroblastoma Neuro 2a cells are known to extend neurite-like processes in response to gangliosides added to the culture medium. We compared the structural features of proteoglycans (PG) synthesized by conventional Neuro 2a cells with those of neurite-bearing cells. Two different proteoglycans labeled with [³⁵S]sulfate, namely, chondroitin sulfate proteoglycan (CS-PG) and heparan sulfate proteoglycan (HS-PG), were found both in the cell layer and in the culture medium of the conventional cells. CS-PG isolated from the cell layer had a K_av value of 0.38 on Sepharose CL-6B, and had CS side chains with Mr of 27,000. HS-PG in the cell layer was slightly larger (K_av of 0.33) in terms of hydrodynamic size than CS-PG, and the apparent Mr of the heparan sulfate side chains was 10,000. The structural parameters of CS-PG and HS-PG isolated from the medium were almost identical to those of the PGs in the cell layer. In addition to these PGs, single-chain HS, with an average Mr of 2,500, was observed only in the cell layer and this component was the major sulfated component in the cell layers of both control and ganglioside treated cells. The neurite-bearing cells also synthesized both CS-PG and HS-PG which were very similar in hydrodynamic size to those synthesized by the conventional cells, but the size of HS side chains was greater. Radioactivity, as³⁵S, of each sulfated component from the gangliosideteated culture seemed to be slightly less than that of the corresponding component from the control culture. These findings indicate that the marked morphological change in Neuro 2a cells, induced by gangliosides is not accompanied by major changes in the synthesis of PGs.