The effect of light on the growth rate of intertidal Acropora pulchra (Brook) from Phuket,Thailand, lat. 8°N

Series of apices of Acropora pulchra from an intertidal reef at Phuket, Thailand, were grown at different depths in the sea, and the length growth was monitored at 12–24 h intervals with laser diffraction. The growth rates of actively growing apices were normally distributed and showed a high variability, with an average coefficient of variation of 58%. There was a highly significant difference in average growth rate between adjacent colonies. A significant linear relationship was found between irradiance and length growth, with a saturating level at 300–400 Wm^-2. At 1000 Wm^-2 length growth was significantly reduced. Under normal daylight conditions, day and night growth rates were equal.     

Distribution of opioidergic,sympathetic and neuropeptide Y-positive nerves in the sphincter of Oddi and biliary tree of the monkey,Macaca fascicularis

Summary The opioidergic, sympathetic and neuropeptide Y-positive innervation of the sphincter of Oddi (common bile duct sphincter and pancreatic duct sphincter), as well as other segments of the extrahepatic biliary tree was studied in the monkey by use of immunohistochemistry. Methionine-enkephalin-positive nerves were seen to innervate the smooth muscle of all portions of the sphincter of Oddi and also local ganglion cells. No methionine-enkephalin-positive nerves could be detected in the common bile duct, pancreatic duct or gallbladder. Tyrosine hydroxylase-positive nerves occurred between smooth muscle bundles and also ran to local ganglion cells as well as along the common bile duct. Neuropeptide Y-positive nerves were observed within smooth muscle of the sphincter of Oddi (all portions), common bile duct, pancreatic duct and gallbladder. No evidence of any differential innervation of the pancreatic duct and common bile duct sphincters could be detected with these markers.     

Differences in reactivity of confluent and nonconfluent cultures of human endothelial cells toward thrombin-stimulated platelets or heparinized salt solution

Summary This study examined whether nonconfluent endothelial cell cultures reacted differently than confluent ones toward thrombin-stimulated platelets or a heparinized salt solution. The adherence to the endothelial cell cultures of⁵¹Cr-labeled human platelets stimulated at different thrombin concentrations was studied. There was significantly higher adherence of stimulated platelets to nonconfluent cultures compared with confluent ones. This was confirmed by scanning electron microscopy, which also revealed a tendency for the platelets to adhere at the cell periphery. Electron microscopy also showed that thrombin-stimulated platelets induced endothelial cell contraction. Part of the peripheral endothelial cell surface toward the bottom of the culture dish was inverted, facing the lumen of the dish. This phenomenon was particularly seen in nonconfluent cultures. When⁵¹Cr-labeled endothelial cultures were incubated with a mildly injurious fluid as heparinized sodium acetate and 20% serum, at 20° C for 30 min, the nonconfluent cultures showed significantly more cell detachment and release of⁵¹Cr than the confluent ones. We conclude that under the conditions of the present experiments there are differences in the reactivity of confluent and nonconfluent endothelial cell cultures. These differences probably reflect biological dissimilarities. In experiments where properties of cultured endothelium are studied, care should be taken that the degree of confluency is standardized.     

Ein überzähliger genitalapparat bei einem rhabdocölen Turbellar

A specimen of Ethmorhynchus anophthalmus Meixner 1938 contains a complex of supernumerary genital organs in front of the pharynx. The phenomenon elucidates some traits in the morphogenesis of the atrial organs.

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Abkürzungen in den Abbildungen At Atrium genitale - Bu Bursa - Ci Cirrus des Kopulationsorganes - Dc Ductus communis - Ho Hoden - Ke Keimstock - Kop Kopulationsorgan - Ph Pharynx - R Rüssel - Sa Samenblase     

Microtubule-associated distribution of specific granules and secretion of atrial natriuretic factor in primary cultures of rat cardiomyocytes

A close spatial relationship between specific granules containing atrial natriuretic factor (ANF) and microtubules was demonstrated in primary cultures of neonatal rat cardiac myocytes. For the detection of specific granules and microtubules, the myocytes were double immunolabelled with antibodies against -ANF and -tubulin and examined by conventional fluorescence or laser scanning confocal microscopy. In addition, the ultrastructural distribution of specific granules was demonstrated by electron microscopy. In the atrial myocytes, ANF was stored in numerous specific granules that were mainly localized in the perinuclear sarcoplasm. In the ventricular myocytes, however, a minority of the cells (10%) exhibited limited ANF immunoreactivity after 4 days in culture. Microtubules were present throughout the sarcoplasm of the myocytes. They were most densely packed in the perinuclear regions. Depolymerization of the microtubules with nocodazole was followed by dispersal of ANF immunostaining both in the atrial myocytes and in the ventricular myocytes exhibiting ANF immunoreactivity. When the microtubules were allowed to recover, the perinuclear distribution of specific granules, as seen in non-treated myocytes, reappeared. Measurements of secreted immunoreactive ANF by radioimmunoassay revealed that the secretion of ANF from atrial myocytes into the medium was significantly reduced following nocodazole treatment, whereas a similar decrease in secretion from ventricular myocytes was not observed. These findings indicate that ANF-containing specific granules are closely associated with microtubules within the myocytes. It is suggested that secretion of ANF from the atrial myocytes, in contrast to the ventricular myocytes, is microtubule-dependent.     

Effects of acid wastes from titanium dioxide production on biomass and species richness of benthic algae

Titanium dioxide wastes are suspected to be toxic to rocky shore communities in an estuary in southeast Norway. An experimental project lasting two years examined whether titanium dioxide wastes affected recolonization by rocky shore organisms. The experiments were performed in situ in six tanks (each with 9 m³ brackish water) at two different levels of salinity. Three different concentrations of industrial waste water were used. The growth season in 1986 was dry and sunny compared to 1987, causing reduction of growth on exposed granite chips compared to controls. At the two highest waste concentrations in the tanks, Fucus serratus was observed with necrotic tissue both years, and in 1986 benthic diatoms were scarce.     

The effect of lead,cadmium, and mercury on the increase in length of five intertidal fucales

The increase in length of Pelvetia canaliculata (L.) Dec. et Thur., Fucus spiralis L., F. vesiculosus L., F. serratus L., and Ascophyllym nodosum (L.) Le Jolis was measured in various concentrations of lead, cadmium, and mercury during a period of 9–10 days. Concentration ranges of the three metals were 45 2600 μg 1, 1.5 1040 μg 1 and 0.9 1250 μg 1, respectively.Significant reductions of growth rate compared with the controls were observed at ? 810 μg 1 of lead, ? 450 μg/l of cadmium, and ? 10 μg/l of mercury, and regressions of growth reduction on log concentration were indicated.Growth was significantly enhanced in Pelvetia canaliculata and Ascophyllum nodosum when exposed to cadmium, and in this case there was a significant regression of growth iincrease on log concentration. The growth of Pelvetia canaliculata was also enhanced at all concentrations of lead.     

Structural studies of the polysaccharide antigen of Eubacterium saburreum, Strain L 32

The structure of the polysaccharide antigen produced by Eubacterium saburreum, strain L 32, has been investigated. The principal methods used were methylation analysis, graded hydrolysis with acid, and n.m.r. spectroscopy. The polysaccharide, which contains the unusual sugar 3,6-dideoxy-D-arabino-hexose (tyvelose, Tyv), is composed of trisaccharide repeating-units having the following structure:

     

Autoradiographic study on the localization of estradiol-17β in neonatal mouse uterus and cervix

Summary The uptake of ³H-estradiol-17 in the neonatal mouse uterus and cervix has been studied by an autoradiographic method. When the radio-active hormone is administered in vivo and in vitro, grains are found to be concentrated above the nuclei both in the uterine and cervical epithelium and stroma. Grain counts revealed that the nuclear concentration of grains is higher at 4 h than at 2 h after isotope injection. The cervical epithelium has a higher nuclear concentration than the uterine epithelium both in vivo and in vitro. In the stroma, this situation is reversed except after in vitro treatment of the tissues.In the cervix, more of the hormone seems to be located within the nucleus while in the uterus a higher proportion of the grains are found in the vicinity of the nuclear periphery.Although the nuclear concentration of grains is higher at 4 h than at 2 h, the number of grains above the sections is lower at 4 h. Both in vivo and in vitro, the number of grains is higher above the stromal than above the epithelial compartments of the uterus and cervix.Five days old animals showed the same labeling pattern. The differences in uptake and distribution of ³H-estradiol are discussed in relation to other known differences in the hormone responsiveness in these tissues.We are greatly indebted to Professor W.E. Stumpf and the Laboratories for Reproductive Biology, University of North Carolina Medical School for the opportunity to study the method of dry mount autoradiography. The work has been supported by the Norwegian Research Council for Science and the Humanities and by the Norwegian Cancer Society (Landsforeningen mot Kreft)