Localization of tropomyosin in sea urchin eggs

Localization of tropomyosin in sea urchin eggs was investigated immunohistochemically. A rabbit antiserum against tropomyosin prepared from lantern muscle of the sea urchin was used for the indirect immunofluorescence staining of unfertilized and fertilized eggs. The tropomyosin-specific fluorescence was observed at the peripheral region beneath the plasma membrane, mitotic apparatus and contractile ring. The mitotic apparatus isolated from sea urchin eggs was also stained with the anti-tropomyosin serum.     

Effects of 2-bromo-α-ergocryptine on β-endorphin-induced growth hormone,prolactin and luteining hormone release in urethane anesthetized rats

Adult male rats were injected intraperitoneally either with saline or 2-Br- α-ergocryptine(CB-154)(10 ng/0.5 ml/rat) 30 min prior to an intraventricular injection of saline or β-endorphin (1 μg/10 μl or 5 μg/10 μl) and 30 min after β-endorphin, they were sacrificed by decapitation. Intraventricular injection of β-endorphin elicited significant increases in serum GH, prolactin and LH levels in a dose-related manner. Pretreatment with CB-154 inhibited the release of GH, prolactin and LH induced by β-endorphin. These results indicate that the stimulatory effects of β-endorphin on GH, prolactin and LH may be involved in an inhibition of dopaminergic mechanism in the central nervous system.     

Spectral dependence of the light-induced geotropic response in Zea roots

The induction by light of geotropic responsiveness in the primary roots of Zea mays L. (cv. Golden Cross Bantam 70) was found to be governed by the all-or-none law. The response was induced by light energies above a threshold value, but the maximal curvature of geo-stimulated roots was constand irrespective of the light energy above that threshold. The action spectrum for this light effect showed a large peak at 650, a small peak at 410, and a shoulder at 663 nm. The effect of red light was not reversed by far-red light. Thus, the geotropic response in Zea roots may not be controlled by phytochrome.     

Effects of IAA on oxygen-sensitive growth and on hydroxyproline protein level in cell wall

Indole-3-asscetic acid (IAA) accelerated the incorporation ofradioactivity derived from ¹⁴C-proline into the SLS-insolublecell wall fraction only when the sections were exposed to lowoxygen concentrations. However, IAA showed no effect on theratio of hydroxyproline to proline incorporated into the SLS-insolublefraction in both 20% and 8% O₂-treated sections. The amountof hydroxyproline rigidly bound to the cell wall increased withincreasing IAA concentration in 8% O₂-treated sections, whilethat of the 20% O₂-treated ones decreased with IAA treatment. On the other hand, IAA increased the amount of ¹⁴C-labeled hydroxyprolineincorporated into the SLS-insoluble fraction of sections treatedwith cycloheximide, and their elongation was greatly inhibited. Based on the results that O₂ and IAA affect the auxin-inducedand the oxygen- sensitive growth differently, we suggest thatboth types of growth may antagonize each other in response tochanges in O₂ and IAA concentrations, resulting in balancedgrowth in the cell. (Received October 7, 1977; )     

Affinity chromatography of an ethylene-synthesizing enzyme from red alga Porphyra tenera on an immobilized inhibitor of ethylene evolution

A method was established to purify acrylate decarboxylase fromPorphyra tenera by affinity chromatography using a proteinaceousinhibitor of ethylene evolution in marine algae, isolated fromP. tenera as a ligand. The proteinaceous inhibitor was covalentlycoupled to porous glass via four different spacer arms. Theporous glass-aminopropyltriethoxysilane-succinatephenylendiamine-succinate-inhibitorappeared to be the best derivative for retaining acrylate decarboxylaseextracted from P. tenera. Acrylate decarboxylase was extracted from 10 kg of P. teneraand semi-purified by ammonium sulfate. preparation and gel filtrationon Sephadex G-100. The active fraction was applied to an affinitycolumn. Acrylate decarboxylase was eluted in the starting buffercontaining 0.2 M NaCl. Ethylene formation from acrylate wasdetected in the presence of this enzyme extract, but not inthe case of the boiled enzyme extract. Acrylate decarboxylasewas inhibited by the inhibitor isolated from P. tenera. Thesefacts indicate that the formation of ethylene in marine algaefrom acrylate proceeds enzymatically. ² Present address: Division of Environmental Biology, NationalInstitute for Environmental Studies, Yatabe, Ibaraki 300-21,Japan. (Received July 13, 1976; )     

Appearance of newly formed mRNA and rRNA as ribonucleoprotein-particles in the cytoplasmic subribosomal fraction of pea embryos

Incorporation studies with ³H-uridine or ³H-adenosine showedthat germinating pea embryos synthesize all types of poly A(+)RNA, rRNA and 4–5S RNA at the early stage of germination.After the pulse labeling for 30 min, only heterodisperse RNAand 4–5S RNA appeared in the cytoplasm as labeled RNAspecies. At this time the radioactivity was associated withcytoplasmic structures heavier than 80S and RNP particles of68–70S, 52–55S, 36–38S and 20–22S whichare presumed to be free mRNP particles in plants. When the pulse-labeledembryos were incubated for a further 60 min in an isotope-freemedium, the labeled 17S and 25S rRNA emerged in the cytoplasm,together with labeled heterodisperse and 4–5S RNAs. Moreradioactivity accumulated in the regions of the polysome, 62–65Sand 38–42S particles. The results of analysis of RNAsextracted from the whole cytoplasm, polysome or subribosomalfractions indicated that small subunits of newly formed ribosomesappear more rapidly in the cytoplasm than new large subunits,which accumulate for a while as free particles in the cytoplasmthen are incorporated into polysomes. The actino-mycin treatmentwhich caused preferential inhibition of rRNA synthesis reducedthe accumulation of free, newly formed ribosome subunits andpartially permitted detection of the presumed mRNP particlesin the subribosomal region even after the chase treatment. (Received June 28, 1976; )     

Purification of human renin

Human renin was purified 2,800-fold from a partially purified preparation to an electrophoretically homogeneous state by a series of three different types of affinity chromatography and two additional conventional chromatographic steps at a yield of 9.7%. This amounts to a 420,000-fold purification from a crude kidney extract. This pure human renin preparation has a specific activity of 830 Goldblatt unit/mg and is stable at pH 6.2 and 4°C at least for 3 weeks.     

Properties and biosynthesis of cell wall-bound acid phosphatase in Aspergillus nigerx

Acid phosphatase (EC 3.1.3.2 [EC] ) of Aspergillus niger myceliumwas distributed exclusively in the cell wall and soluble fractions,whereas alkaline phosphatase was distributed in the solubleand particulate fractions but only slightly in the cell wallfraction. Cell wall-bound acid phosphatase was released by fungal-walllytic enzymes such as snail gut juice. Cell wall-bound, released,and soluble acid phosphatases showed very similar enzymaticproperties except that the bound enzyme was more stable to heatand detergents. By DEAE-cellulose chromatography, the releasedacid phosphatase was found to correspond to acid phosphatasesI A, IB and II in the soluble fraction. When phosphate in the medium was consumed, the acid phosphataseactivity of the soluble fraction increased more rapidly thanthat of the cell wall fraction. When phosphate was added tothe derepressed culture, the acid phosphatase activity of thesoluble fraction decreased after a short lag period, while thatof the cell wall fraction continued to increase. When labeledamino acid was added to the derepressed culture, it was incorporatedinto the soluble acid phosphatase without a lag period, whileit was incorporated into the cell wall phosphatase after a lagperiod. From these observations, acid phosphatase was consideredto be synthesized first as the soluble form and then integratedinto the cell wall. ¹ The present experiments were carried out, for the most part,at the Institute of Applied Microbiology of the University ofTokyo. (Received January 19, 1976; )     

Continuous production of 6-aminopenicillanic acid from penicillin by immobilized microbial cells

Summary For continuous production of 6-aminopenicillanic acid (6-APA) the microbial cells ofEscherichia coli ATCC 9637 having high penicillin amidase (penicillin amidohydrolase, E.C. 3. 5. 1. 11) activity were immobilized by entrapment in a polyacrylamide gel lattice.Enzymatic properties of penicillin amidase of the immobilizedE. coli cells were investigated and compared with those of the intact cells. With regard to optimal pH and temperature, no marked difference was observed. The heat stability was somewhat increased by immobilization of the cells.The enzyme activity of the immobilized cell column was stable, and its half-life was 17 days at 40°C and 42 days at 30°C. From the effluent of the column, 6-APA was easily obtained in a good yield.Abbreviations 6-APA 6-aminopenicillanic acid - BIS N,N-methylenebisacrylamide - DMAPN -dimethylaminopropionitrile - SV space velocity