Inducibility of benzoate oxidizing cell activities in Acinetobacter calcoaceticus strain Bs 5 by chlorobenzoates as influenced by the position of chlorine atoms and the inducer concentration

Summary Among four chlorobenzoates tested, only 3-chlorobenzoate and 4-chlorobenzoate were capable of inducing benzoate oxidizing cell activities in Acinetobacter calcoaceticus strain Bs 5, whereas 2-chlorobenzoate and 2,6-dichlorobenzoate were not. With the monochlorobenzoates, this inducing capability decreased with increasing proximity of the chlorine atom to the carboxyl group, i.e. in the order: 4-chlorobenzoate > 3-chlorobenzoate > 2-chlorobenzoate. It is therefore supposed that the induction of benzoate oxidizing cell activities is inhibited primarily be sterical influences of the chlorine substituents of the various chlorobenzoates.With decreasing concentration of 3-chlorobenzoate and 4-chlorobenzoate, the induction of benzoate oxidizing cell activities decreased. Below a critical concentration of 1 M, these activities were no longer detectable in the cells of Acinetobacter calcoaceticus, with the consequence that below this concentration limit, the degradation of 3-chlorobenzoate and 4-chlorobenzoate was no longer possible.     

Microbial sensors for determination of aromatics and their chloroderivatives I. Determination of 3-chlorobenzoate using a Pseudomonas-containing biosensor

Summary An amperometric biosensor for the determination of benzoate and 3-chlorobenzoate using Pseudomonas has been developed. The influence of preincubation of the biosensor with desired substrates on sensitivity and specificity was investigated. The Pseudomonas sensor was more sensitive to benzoate and 3-chlorobenzoate than to 2- and 4-chloro-, 2,4-dichlorobenzoate and 2,4-dichlorophenol. Incubation of the sensor with benzoate and 3-chlorobenzoate enhanced the activity of the microbial sensor. Other chlorobenzoates tested caused a decrease of sensitivity. A linear relationship between the current range and the concentration of benzoate was observed up to 160 mol/l. In the case of 3-chlorobenzoate a linear relationship was observed for concentrations up to 200 mol/l. The signal is reproducible within 5.5% when the test solution contains 40 mol/l of 3-chlorobenzoate. Offprint requests to: K. Riedel     

Clonal propagation of Callistemon by tissue culture techniques

Callus development in Callistemon viminalis was readily achieved when axillary buds derived from nodal tissue were placed in a medium containing macro- and micro-nutrients, sucrose (0.06 M), inositol (300 M), nicotinic acid (20 M), pyridoxine hydrochloride (3 M), thiamine hydrochloride (2 M), riboflavin (10 M), cytokinins (5 M) and auxins (0.1 M). The presence of benzylaminopurine (5 M) and p-chlorophenoxyacetic acid (0.1 M) promoted the most vigorous callus development and sprout formation. Rooting of nodal material was rare but occurred readily following the transference of sprouts developed on callus to a basal medium containing sucrose and salts. Root initiation was stimulated, however, by the presence of auxins. Chlorophenoxyacetic acid while stimulating root initiation repressed root growth. Indole butyric acid stimulated both root initiation and shoot growth at concentrations of 0.005 to 0.1 M. The treatment of choice for rooting and shoot growth was the addition of indole butyric acid at a concentration of 0.01 M.     

Soil microbial population dynamics following bioaugmentation with a 3-chlorobenzoate-degrading bacterial culture

Changes in microbial populations were evaluated following inoculation of contaminated soil with a 3-chlorobenzoate degrader. Madera sandy loam was amended with 0, 500, or 1000 g 3-chlorobenzoate g^-1 dry soil. Selected microcosms were inoculated with the degrader Comamonas testosteroni BR60. Culturable bacterial degraderswere enumerated on minimal salts media containing 3-chlorobenzoate. Culturableheterotrophic bacteria were enumerated on R2A. Isolated degraders were grouped by enterobacterial repetitive intergenic consensus sequence-polymerase chain reaction fingerprints and identified based on 16S ribosomal-DNA sequences. Bioaugmentation increased the rate of degradation at both levels of 3-chlorobenzoate. In both the 500 and 1000 g 3-chlorobenzoate g^-1 dry soil inoculated microcosms, degradersincreased from the initial inoculum and decreased following degradation of 3-CB.Inoculation delayed the development of indigenous 3-chlorobenzoate degrading populations. It is unclear if inoculation altered the composition of indigenous degrader populations. In the uninoculated soil, degraders increased from undetectable levels to 6.6 × 10⁷ colony-forming-units g^-1 dry soil in the 500 g 3-chlorobenzoate g^-1 dry soil microcosms, but none were detected in the 1000 g 3-chlorobenzoate g^-1 dry soil microcosms. Degraders isolated from uninoculated soil were identified as one of two distinct Burkholderia species.In the uninoculated soil, numbers of culturable heterotrophic bacteria initially decreased following addition of 1000 g 3-chlorobenzoate g^-1 dry soil. Inoculation with C. testosteroni reduced this negative impact on culturable bacterial numbers. The results indicate that bioaugmentation may not only increase the rate of 3-chlorobenzoate degradation but also reduce the deleterious effects of 3-chlorbenzoate on indigenous soil microbial populations.     

Endogenous phosphorylation of rat brain synaptosomal plasma membranes in vitro: Some methodological aspects

The time course of endogenous phosphorylation in vitro of total or separted synaptic plasma membrane proteins (SPM) has been correlated with that of hydrolysis of the phosphate donor (ATP) in the incubation medium. The ATP/SPM ratio in the medium was varied. In a low-ratio medium (7.5 M ATP; 2.2 g SPM/l) a complete hydrolysis of ATP occurred almost instantaneously as was measured by the release of free phosphate in and the disappearance of ATP from the medium. As a consequence, only a very short peak of phosphorylation, followed by dephosphorylation was observed. However, when higher ATP/SPM ratios were used (200 M ATP; 0.4 g SPM/l and 500 M ATP; 0.4 g SPM/l), the incorporation of phosphate into SPM proteins was linear for 20 sec, and the maximum level of phosphate incorporation was increased. Similar results were obtained after separation of³²P-labeled phosphoproteins by slab gel electrophoresis. However, analysis of the autoradiographs obtained fromone SPM preparation under different ATP/SPM ratios revealed dependence of phosphorylation of individual protein bands on the conditions used.     

Saccharomyces cerevisiae 2-mum DNA. An analysis of the monomer and its multimers by electron microscopy.

Summary The non-tandem inverted duplication in the 2-m DNA of Saccharomyces cerevisiae has a length of 0.19 m and is located asymmetrically along the molecule. The majority of the dumb-bell structures that are formed upon denaturation and selfannealing of the 2-m monomer consists of the renatured inverted duplication sequences as double stranded stem and two single stranded loops of 0.67 m±0.06 m (S-loop) and 0.86 m±0.05 m (L-loop) length. Two additional size classes which comprised 5–10% of the measured molecules had contour lengths of around 1.7 m and 2.1 m. The smaller dumb-bells contained two S-loops and the larger dumb-bells contained two L-loops as was shown by heteroduplex mapping with an HindIII fragment from the L-loop. Two models which assume illegitimate or site specific recombination, are presented to explain the generation of double S-loop and double L-loop molecules. At least part of the 4-m and 6- circular molecules present in the yeast supercoiled DNA fraction are shown to be dimers and trimers of 2-m monomers, but often with inverted loop segments most probably due to intramolecular recombination between sequences of the inverted duplication.2-m DNA is used to indicate the supercoiled DNA fraction although in our measurements the average monomeric length is 1.9 mPart of this work has been presented at the Conference: The Genetics and Biogenesis of Chloroplasts and Mitochondria, Munich, August, 1976     

Action of phenazine methyl sulfate,inhibitors, and uncouplers on the light-induced proton transport by cells ofRhodospirillum rubrum

Summary Suspensions of log phase cells ofRhodospirillum rubrum at pH 5.5 show a light-induced decrease in the pH of the medium which is reversed during the subsequent dark period. The velocity and magnitude of the pH change were the same whether the cells were bubbled with air, CO₂-free air or N₂ during experimentation. The pH response is temperature dependent. Phenazine methyl sulfate (PMS) at concentrations above 0.05mm stimulates the light-induced pH change. PMS at 1mm gives a 2-fold increase in the initial rate upon illumination and a 1.5-fold increase in the total change in pH after 2 min of illumination. The inhibition of the proton transport by 10 g/ml antimycin A or 20 m 2-n-heptyl-4-hydroxyquinoline-N-oxide can be partially relieved by PMS. However, inhibition of the light-induced proton transport with 0.5mm 2,4-dinitrophenol or 3 m carbonylcyanide-m-chlorophenylhydrazone (CCCP) cannot be overcome by addition of PMS. Valinomycin, at a concentration of 3 m, caused a slight stimulation of the light-induced proton transport in the presence of 200mm KCl. The inhibition of proton transport by 3 m CCCP was partially relieved with 3 m valinomycin in the presence of 200mm KCl, but the antibiotic was without effect when the cells were suspended in 200mm NaCl. The results are discussed in terms of current theories of the action of PMS, antimycin A, valinomycin, and uncouplers on the light-induced electron flow and photophosphorylation inR. rubrum.     

Differential maturation of μ and δ opioid receptors in the chick embryonic brain

The developmental profiles of the binding of and opiate receptors agonists was investigated using the chick embryo brain. Binding of opioids was performed at embryonic days 5, 6, 15, 18, and 20 in the developing chick embryo brain. [³H]dihyromorphine was used as a ligand and with 5×10^–7 M levorphanol for non-specific binding, and [³H](d-Ala²-d-Leu⁵)-enkephalin was used as a with 5×10^–7 M (d-Ser-Gly-Phe-Leu-Thr)-enkephalin for non-specific binding. Crude membranes were prepared from whole brain at days, 5, 6 and cerebral hemispheres at days 15, 18, and 20 of embryonic age. Both and opiate receptors were present during early embryogenesis and as early as day 5. Analysis of binding sites revealed high and low affinity sites during early embryogenesis but only one site. By 18 days of embryonic age, only one site remained. This developmental change is interpreted as a transitory state of the receptor to the adult pattern. The presence of only one site is constant throughout embryonic age; it is high during early embryogenesis reaching a lower level by 18 days. The presence of a dual binding site pattern for the receptor in early embryogenesis is implicated to have a functional significance in the pluripotential role of the endogenous opioids in early development.     

Responses of nitrogen-fixing and nitrate-supplied alfalfa (Medicago sativa L.) to iron chelates in an alkaline hydroponic medium

Ferric ethylenediamine di-(o-hydroxyphenylacetate) (FeEDDHA) and ferric hydroxyethylethylenediaminetriacetic acid (FeHEDTA) were evaluated as Fe sources for hydroponic growth of alfalfa (Medicago sativa L., cv. Mesilla), either dependent on N₂ fixation or supplied with NO₃. The hydroponic medium was maintained at pH 7.5 by addition of CaCO₃. Nitrogen-fixing cultures were inoculated with Rhizobium meliloti 102 F51 and grown in medium without added nitrogen. After five to seven weeks of growth under greenhouse conditions, plants were harvested. Nitrogen fixation was measured by the acetylene reduction method.When FeEDDHA was supplied, growth of alfalfa, whether dependent on N₂ fixation or supplied with NO₃, was severely limited at concentrations typically used in hydroponic medium (10 or 20 M). Maximum yield of NO₃-supplied alfalfa was obtained at 100 M while maximum yield of N₂-fixing alfalfa was obtained in the range of 33 to 200 M FeEDDHA. Nodule fresh weights and N₂ fixation rates increased with FeEDDHA concentration up to 33 M and remained essentially constant up to 200 M. With FeHEDTA, maximum yields of both NO₃-grown and N₂-fixing alfalfa were obtained at 10 M. Growth of NO₃-supplied plants was inhibited at 200 M FeHEDTA while growth of N₂-fixing plants was inhibited at 100 M FeHEDTA. The numbers of nodules per plant increased between 3.3 and 10 M FeHEDTA; however, inhibition of nodule formation occurred at a concentration of 33 M or higher. Nodule weights per plant and N₂ fixation rates were depressed at 3.3 M as well as at 100 M FeHEDTA. The results suggest that alfalfa dependent on N₂ fixation is more sensitive to limited Fe availability than alfalfa supplied with NO₃.     

Guanosine enhances glutamate uptake in brain cortical slices at normal and excitotoxic conditions

1. The effect of guanosine on L-[2,3-³H]glutamate uptake was investigated in brain cortical slices under normal or oxygen–glucose deprivation (OGD) conditions.2. In slices exposed to physiological conditions, guanosine (1–100 M) stimulated glutamate uptake (up to 100%) in a concentration-dependent manner when a high (100 M) but not a low (1 M) concentration of glutamate was used.3. In slices submitted to OGD, guanosine 1 and 100 M also increased 100 M glutamate uptake (38 and 70%, respectively).4. The increasing of glutamate and taurine released to the incubation medium in cortical slices submitted to OGD were significantly attenuated by the presence of guanosine in the incubation medium.5. Guanosine prevented the increase in propidium iodide incorporation into cortical slices induced by OGD, indicating a protective role against ischemic injury.6. These results support the hypothesis of a protective role for guanosine during brain ischemia, possibly by activating glutamate uptake into neural cells.     

The endogenous development of four new species of Isospora Schneider, 1881 (Apicomplexa: Eimeriidae) from Australian geckos

Four new species of Isospora are described from Australian geckoes. Isospora gehyrae n. sp. from Gehyra cf. variegata in South Australia have 18.5-22.5×17.5–20.0 m oöcysts with 10.0-12.5×7.5-9.0 m sporocysts; endogenous stages develop in the host cell cytoplasm. Of the two species found in Heteronotia binoei from northern Queensland, Isospora cytoheteronotis n. sp., with oöcysts of 20.0-26.0×17.5-25.0 m and sporocysts of 10.0-13.5×7.5-11.5 m, undergoes endogenous development in its host cell cytoplasm, whereas I. nucleoheteronotis n. sp., with oöcysts of 17.5-22.5×17.5-21.5 m and sporocysts of 9.0-12.5×6.5-10.0 m, develops in the host cell nucleus. I. oedurae n. sp. from Oedura rhombifer in northern Queensland has oöcysts of 22.5-25.0×22.5-24.0 m and sporocysts of 12.5-14.0×7.5-11.5 m, and undergoes endogenous development in its host cell nuclei.     

Oocysts of Isospora ernsti n. sp. and Isospora blagburni n. sp. (Apicomplexa: Eimeriidae) from the black-capped bulbul,Pycnonotus xanthopygos

Oocysts of Isospora ernsti n. sp. and Isospora blagburni n. sp. are described from the black-capped bulbul Pycnonotus xanthopygos from Lincoln Park Zoo, Chicago, Illinois. The bird came from southwestern Africa seven years earlier. I. ernsti oocysts are ellipsoidal to bluntly ovoid, 28–38 × 23–31m (mean 34 × 28 m) and have a single-layered oocyst wall. Micropyle, oocyst residuum and polar granules are absent. Sporocysts are elongate ovoid, 24–30 × 11–16 m (mean 27×13 m). Stieda and substiedal bodies and sporocyst residuum are present. I. blagburni oocysts are spherical to subspherical. 21–28 × 19–26 m (mean 25 × 23 m) and have a single oocyst wall. Sporocysts are ovoid and 17–23 × 10–13 m (mean 20 × 12 m). Stieda and substiedal bodies and sporocyst residuum are present.     

Stimulation of ethylene production by catecholamines and phenylethylamine in potato cell suspension cultures

The catecholamines (50 M dopamine, 50 M norepinephrine and 100 M epinephrine) and phenylethylamine (200 M) were found to stimulate ethylene production in potato suspension cultures. When 100 M amino-oxyacetic acid was added together with epinephrine, ethylene release returned to control levels. The endogenous 1-aminocyclopropane-1-carboxylic acid levels were increased in parallel with the release of ethylene, suggesting that the observed effect probably occurs via regulation of aCC synthase. Our results suggest that there is a link between these naturally occurring monoamines and ethylene in plants.Abbreviations AOA amino-oxyacetic acid - ACC 1-aminocyclopropane-1-carboxylic acid - DA dopamine - NE norepinephrine - E epinephrine - CA catecholamines - PEA phenylethylamine     

Intestinal microflora in the deep-sea isopodBathynomus giganteus

Observations with the scanning electron microscope showed that the deep-sea isopodBathynomus giganteus harbors a dense microflora within the digestive tract. The gut microflora is composed of a diversity of microorganisms, including an unusually large bacterial morphotype that predominates almost exclusively in the anterior end of the hindgut. The majority of these large bacteria measured 1.9 m×8.5 m and many reached a size of 2.0 m×10.0 m.     

Multiple shoot-bud formation and plantlet regeneration on Castanea sativa Mill. seeds in culture

Primordial initiation and development of shoot-buds has been accomplished by using shoots derived from chestnut (Castanea sativa Mill) seedlings cultured with added 6-benzylaminopurine (BAP). Germination of chestnut seeds in the presence of BAP (4 – 40 M) stimulated varying numbers of shoot-buds in those areas of the main axis that were favorably altered. When excised single shoots from these treated seeds were subcultured on a fresh medium containing BAP (4 – 40 M) continual shoot production was observed. Bud growth and shoot elongation were stimulated by transferring cultures to a reduced concentration of BAP (2 M) plus indole-3-butyric acid (IBA 0.4 M). Plant regeneration occurred in the presence of IBA (0.8 M) after a preconditioning treatment in which naphthaleneacetic acid (NAA 50 M) and kinetin (k 2 M) were applied to the tissue culture shoots for 7 days in light.     

Catabolic potential of multiple PCB transformation systems in Rhodococcus sp. strain RHA1

Summary Polychlorinated biphenyl (PCB) transformation activity of a strong PCB degrader, Rhodococcus sp. strain RHA1, was examined in different concentrations of PCBs. A extremely strong PCB transformation activity was observed on 30 g PCB/ml. At 50 and 100 g/ml, transformation activities were diminished. In the case of bphA insertion mutant, RDA1, transformation activity in the presence of ethylbezene was poor even at 30 g/ml. This indicated that the bphA dependent system would play a major role in PCB transformation by RHA1. Greater transformation activity of RHA1 was observed in the presence of ethylbenzene than in the presence of biphenyl.     

Morphology and structural organization of spiracles in femaleArgas (Persicargas) walkerae (Acari: Argasidae)

Scanning electron microscopical investigations of fractures and corrosion casts of the spiracles from femaleA. walkerae ticks revealed a four-part structure, consisting of spiracular plate, ostium and macula forming the external closure, followed by the subostial space and the vestibulum of regulable volume, as well as the atrial chamber as the innermost part from which the main tracheal trunks originate. On the average, the spiracular plate was 158 m long and 188 m at the broadest width. It consisted of a thin, highly perforated external and a thick internal layer, which enclosed the interpedicellar space with numerous stout pedicels. In its posterior region, the spiracular plate was covered by the macula, which was up to 80 m in length and 110 m in width. The interpedicellar cavity opened into the subostial space measuring 95.5 m in length and 159.6m in width, which proceeded into the 112-m long vestibulum. The roof of the vestibulum was flexible and could be everted and inverted. Inverted, the roof formed a quadratic bulge with numerous deep cuticular folds, which confined the lumen of the vestibulum either partially or completely. In corrosion casts, the roof was everted to a length of up to 89.3 m. In the posterior part of the vestibulum, as well as in the initial fourth of the artrial chamber, numerous anvil-, cone-or drop-like cuticular projections were arranged in wedge-like fashion. The atrial chamber was almost spherical with a diameter of 138.4 m. Five main tracheal trunks of different luminal diameter as well as numerous channels opened into the atrial chamber.     

Copper but not iron limitation increases astaxanthin production by Phaffia rhodozyma in a chemically defined medium

The influence of copper (0–32 M) and iron (0–108 M) on growth and astaxanthin production by Phaffia rhodozyma was studied. Copper below 3.2 M increased the astaxanthin content of the cells (from 220 to 287 g g^–1) but at the expense of a slightly decreased growth (from 11.3 to 10.2 mg ml^–1). In contrast, iron below 1 M decreased both the growth and astaxanthin content of the cells. Using copper limitation instead of toxic respiratory inhibitors to improve astaxanthin production has obvious advantages from the product quality, environmental and process operation points of view.     

Different effects of inorganic and triethyl lead on growth and ultrastructure of lily pollen tubes

Summary Pollen tubes ofLilium longiflorum growingin vitro were treated for 1 h with inorganic lead (Pb) and with triethyl lead (TriEL) and studied by light and electron microscopy. Pb was considerably more toxic in relation to inhibition of pollen tube growth (EC₅₀=6 M Pb) than was TriEL (EC₅₀=60 M TriEL). On the other hand, at almost the entire concentration range tested (25-500 M) TriEL caused aberrant tubes and tube swellings. Pb did not cause tube swellings, even at highly growth-impairing concentrations. Pb (60 M) predominantly affected the ultrastructure of the growing cell walls without impairing the distribution of the cell organelles in the tube tips. In contrast, 50 and 100 M TriEL did not visibly influence cell wall ultrastructure but it severely damaged dictyosomes; 100 M TriEL also disturbed the original order of cell organelles in the tube tips. Cortical microtubules were selectively and completely destructed by TriEL at concentrations (50 M) where no effect on polar organization of the tube tips occurred but they remained unimpaired by 60 M Pb, indicating selective and effective interaction of TriEL with these cell organelles.Abbreviations EC⁵⁰ effective lead concentration causing 50% inhibition of pollen tube growth - MTs microtubules - Pb inorganic lead - TriAL trialkyl lead - TriEL triethyl lead     

Role of mitochondria in ethanol tolerance of Saccharomyces cerevisiae

The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate (), fermentation rate (v) or respiration rate () of Saccharomyces cerevisiae wild type strain S288C. Cells which have respiratory metabolism show K _i (ethanol inhibition constant) values for , v and , higher (K _i>1 M) than those of petite mutants or grande strains grown in anaerobiosis (K _i=0.7 M). In addition, the relationship between or v and ethanol concentration is linear in cells with respiratory metabolism and exponential in cells lacking respiration. When functional mitochondria are transferred to petite mutants, the resulting strain shows K _i values similar to those of the grande strain and the inhibition of and v by increasing ethanol concentrations becomes linear.