Action of chlorophyllase purified from rye seedlings on light-harvesting bacteriochlorophyll of chromatophores and spheroplasts from Rhodospirillum rubrum

1. The chlorophyllase [EC 3.1.1.14] purified from greened rye seedlings hydrolyzed the bacteriochlorophyll isolated from Rhodospirillum rubrum, but not the pigment bound to the membrane of chromatophores or spheroplasts from the bacterium. 2. Acetone, if added at such concentrations that the bound bacteriochlorophyll would not be solubilized, enabled the enzyme to hydrolyze the bound pigment. The acetone concentrations required for half the maximum hydrolysis rates were 16% with chromatophores and 7% with spheroplasts. 3. The enzymic hydrolysis of the bound bacteriochlorophyll in the presence of acetone removed bacteriochlorophyllide from the membrane, leaving its esterifying alcohol, possibly all-trans-geranylgeraniol, in situ. 4. Washing of chromatophores with 30% acetone removed about 10% of the bound bacteriochlorophyll. The bound pigment remaining after washing was not hydrolyzed by the enzyme unless acetone was added. 5. It seems possible that light-harvesting bacteriochlorophyll was mostly, if not all, bound to the inner surface of chromatophores (the outer surface of spheroplasts), having its esterifying alcohol residue buried in the membrane and its porphyrin residue emerging from the membrane into the inside solution; thus, chlorophyllase could not make contact with the ester linkage between the esterifying alcohol and porphyrin moieties of the pigment unless the esterifying alcohol residue was partly exposed.     

Modeling of experiments on biofilm penetration effects in a fluidized bed nitrification reactor

A four-component, diffusion-reaction model with double Michaelis-Menten kinetics was used to describe the experimental data obtained from a laboratory biofilm, fluidized-bed nitrification reactor. Theory and experiment demonstrated that the stoichiometric ratio (3.5 mg O(2)/mg NH(4) (+)-N) can be employed as a criterion to determine whether the limiting substrate is oxygen or ammonia. For the present work, in the range of concentrations where limitation occurred, 4 mg/L NH(4) (+)-N and 14 mg/L O(2), the ratio of oxygen to ammonia in the bulk liquid determined which substrate was penetration-limiting-O(2) if <3.5 and NH(4) (+) if > 3.5. Halforder kinetics with respect to the limiting substrate described the apparent overall rates. Simulations provided biofilm concentration profiles which demonstrated the role of the oxygen-ammonia ratio. Experiments indicated that, generally, high NO(2) (-) concentrations can be expected. These depend on the residence time, biofilm area, and oxygen concentration. This dependency was investigated with the model, as was the parametric sensitivity with respect to the saturation constants. Particularly important for the NO(2) (-) levels were the ratios of the saturation constants for oxygen.     

Immunoreactive glucagon in the vascular walls of the rat

We detected immunohistochemically immunoreactive glucagon (IRG) in the smooth muscle of blood vessels and the myoepithelial cell of sweat glands of rats using two antisera against pancreatic glucagon; OAL-123 and 30K. The content of IRG in the blood vessels was found to be 320-1, 270 pg per g wet tissue weight. Filtration of the extracted IRG through a Bio Gel P-30 column yielded a single peak of IRG at 3,500 daltons, the same elution volume of pancreatic glucagon. These findings suggest that the blood vessels of the rats is one of the extrapancreatic sources of IRG in plasma, although physiological role of the IRG is not known.     

Effect of Ferricyanide, Ferrocyanide and KCN on Growth and Flowering in the Short-Day Plant Lemna paucicostata 6746

Flowering in the short-day plant Lemna paucicostata 6746 canbe induced under continuous light by the addition of ferricyanie,ferrocyanide or KCN to M-sucrose medium. Each substance is nearly10 times more effective when the flasks are covered by glassbeakers than when cotton plugs are used. By contrast, when floweringis induced under continuous light by copper or by short-daytreatment, neither flowering nor growth are affected by whetherglass beakers or cotton plugs are used. Ferricyanide, ferrocyanideand KCN are also able to induce long-day flowering when theplants are grown on Msucrose medium in small beakers that areplaced in a covered storage dish that also contains a solutionof one of these compounds. Addition of a KOH trap to the storagedish completely blocks the flowering induced by these compounds.If [¹⁴C]ferrocyanide is added to the storage dish both the M-sucrosemedium and the plants contain significant amounts of radioactivity,the amount of radioactivity being proportional to the floweringresponse. These results indicate that ferricyanide, ferrocyanideand KCN break down to release HCN and that it is the HCN whichis responsible for inducing flowering in L. paucicostata 6746under continuous light. ¹Present address: Department of Biology, Osaka Kyoiku University,Ikeda, Osaka 563, Japan. ²Present address: Institute of Horticulture, The Volcani Center,P. O. B. 6, Bet-Dagan, Israel. (Received January 17, 1983; Accepted March 24, 1983)     

Isolation and Purification of Cytochrome b561 from a Photosynthetic Bacterium, Rhodopseudomonas sphaeroides

Cytochrome b₅₆₁ was removed from chromatophores of a photoanaerobicallygrown Rhodopseudomonas sphaeroides by deoxycholate-cholate andTriton X-100 treatments of the chromatophores. The cytochromewas purified by ammonium sulfate fractionation and gel filtration.Its molecular weight was 45,000 (45 kD) and it was composedof three subunits with molecular weights of 23 kD, 19 kD andless than 6 kD. The cytochrome preparation had absorption maximaat 414 nm in the oxidized form, and at 428, 530 and 561 nm inthe reduced form. Its pi was 4.8. The midpoint potential ofthis cytochrome was 153 mV at pH 7.0. The compound was autooxidizable,and it had cytochrome c oxidase activity. (Received May 16, 1983; Accepted September 8, 1983)     

Improvement of first-service pregnancy rate in cows with gonadotropin-releasing hormone analog

The effect of an intramuscular injection of a new analog of gonadotropin-releasing hormone (GnRH), fertirelin, on the first-service pregnancy rate in cows was investigated by a double blind experiment. A total of 1,194 cows was injected intramuscularly either with 100 mug of GnRH or placebo (physiological saline solution) at the time of first insemination postpartum. Pregnancy rate (number of cows calved/ number of cows serviced) was 57.2 % in 605 cows treated with GnRH, while the performance was 49.7 % in 589 cows of the placebo group. The difference of pregnancy rates in both groups was significant (P<0.05). GnRH injected at insemination was effective, especially in cows at the first and third lactations, cows at 101 days postpartum or later, cows with daily milk yield of 26-30 kg, and also in cows from the area where a regional average fertility was relatively low.     

Long-chain betulaprenol-type polyprenols from the leaves of Ginkgo biloba.

A long-chain betulaprenol-type polyprenol mixture was isolated from the leaves of Ginkgo biloba mainly as acetate. The structure was determined by mass spectroscopy, 1H-n.m.r. spectroscopy and 13C-n.m.r. spectroscopy. The mixture contained polyprenols-14-22, predominantly polyprenols-17, -18 and -19, and consisted of the dimethylallyl terminal unit (omega-terminal), two trans-isoprene residues, a sequence of 11-19 cis-isoprene residues and a terminal hydroxylated isoprene unit (alpha-terminal) aligned in that order. The concentration of these polyprenols in leaves increased from 0.04 to 2.0% of dry wt. with maturing of the leaves, though the content of total lipids was constant. The distribution of chain length in these polyprenols showed little variation throughout the whole life of the leaves.     

Expression in Escherichia coli of chemically synthesized gene for the human immune interferon.

A 454 base pair fragment of double stranded DNA consisting of a gene for a human immune interferon (hIFN-gamma), initiation and termination signals plus appropriate restriction endonuclease sites, was totally synthesized. The synthesis involved preparation of 62 oligodeoxyribonucleotides by rapid, solid phase procedures, and enzymatic ligation of the oligonucleotides. This synthetic gene was expressed in E. coli under the control of the lac UV5 promoter. The product has antiviral activity which was acid labile and completely neutralized by antiserum to hIFN-gamma but not by antiserum to hIFN-alpha or hIFN-beta. Molecular weight of hIFN-gamma produced by E. coli was estimated to be about 32,000 and 17,000 by gel filtration and SDS-polyacrylamide gel electrophoresis respectively.