bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Neuropeptides on the ERG of the Crayfish Orconectes limosus
Authors: Gaus Gabriele , Stieve Hennig
Published: August 2018

CCAP (Crustacean Cardioactive Peptide), Proctolin, FMRFamide, Met- and Leu-enkephalin. Substance P, RPCH (red pigment concentrating hormone) and PDH (pigment dispersing hormone) were applied to the isolated retina of the crayfish Orconectes limosus. Changes in light sensitivity, measured as changes of the amplitude of the electroretinogram (ERG) were observed after application of RPCH, PDH and CCAP. RPCH caused an increase of the ERG amplitude to 133% of its reference value whereas PDH and CCAP decreased the amplitude to 78 % and 30% respectively. A dose-response curve half-maximal effect.
Dynamics and Kinetics of Enzymes Kinetic Equilibrium of Forces in Biochemistry
Authors: Becker Erwin W.
Published: August 2018

To explain the high specificity, high reaction rate, and high thermodynamic efficiency in enzymatic processes, cooperation of the enzyme with a molecular transfer unit is assumed. A “kinetic equilibrium of forces” is suggested, which enables high reaction rates to occur under equilibrium conditions and a thorough examination of the substrate to be made without consumption of free energy. In case of ATPases, ion-binding proteins are the most probable transfer units. By analyzing the elementary effect in muscle contraction it is shown that the new theorem may be of substantial value in elucidating biochemical processes.
Sialic Acid-Binding Proteins: Characterization, Biological Function and Application
Authors: Zeng Fu-Yue , Gabius Hans-Joachim
Published: August 2018

The last decade has witnessed steadily growing support for the notion that the carbohydrate portion of glycoconjugates is not merely an inert structural addition to the protein or lipid backbone. Considerable attention has been given to the chemical composition of glycosidic residues in such heteropolymers. Sialic acids are frequently occurring components of oligosaccharide side chains in glycoconjugates of most higher animals and a few microorganisms. They appear to play an important role as ligands in glycobiological interactions. Mediation of a proposed protein-carbohydrate recognition will necessarily involve a binding protein with the respective specificity. Such proteins thus are able to serve as receptors for certain types of carbohydrate moieties like sialic acids in vivo. Various members of this class of proteins have already proven their value as analytical tools in studying expression and localization of defined sialoglycoconjugates. These proteins attract much attention due to both their functions in situ and their potential as laboratory tools in glycoconjugate research in areas like biochemistry or histology. We present a survey of the purification, characterization and application of this class of proteins to illustrate the status of knowledge and the current directions of research in this field.
Maintenance of Photophosphorylation Despite Inhibition of the Transthylakoid pH Gradient by Tetracaine
Authors: Laasch Henrik
Published: August 2018

The inhibition of the transthylakoid pH gradient, ΔpH, and of photophosphorylation by the local anesthetic tetracaine was investigated with isolated chloroplasts from Spinacia oleracea L. Tetracaine strongly inhibited ΔpH in the presence of low salt concentrations. In the presence of high salt concentrations, the inhibition of ΔpH was much smaller. This effect of salt concentration was observed only when both, cation and anion were easily membrane permeable. It was concluded that the effect of salts on ΔpH inhibition was excerted on the inside of the thylakoid membrane. The rate of photophosphorylation, Vp, driven by the PS Idependent artificial proton carrier phenazine methosulfate decreased with ΔpH in the presence of both, high and low salt concentrations. In contrast, Vp driven by the endogenous proton pumps of PS II + I-dependent linear electron flow was largely independent of ΔpH changes in the presence of low salt concentration. It appeared that energy coupling during linear electron transport, in contrast to artificially produced PS I-dependent coupling, may be localized to membrane-bound proton domains which are not accessible to the employed indicators of ΔpH. The data were discussed with respect to recent hypotheses on localized energy coupling in chloroplasts.
A Simplified Combination of DNA Probe Preparation and Fluorescence in situ Hybridization
Authors: Celeda Dino , Bettag Ulrich , Cremer Christoph
Published: August 2018

Fluorescence in situ hybridization (FISH) has found widespread applications in cytogenetics. So far the standard protocols for probe amplification (and simultaneous labeling) by PCR, nick translation and in situ hybridization involve different buffer systems leading to a number of time consuming washing steps even before hybridization. In this manuscript we show a fast technique of a close combination of DNA probe preparation and in situ hybridization (ISH).

This method was applied to metaphase chromosomes from human lymphocytes fixed on slides. Two specific repetitive DNA probes, the pUC 1.77 DNA probe and the DYZ 1 repetitive DNA fraction were used, amplified and labeled in different ways. Additional experiments with total genomic male human DNA as the DNA probe suggest that this method may be extended to a large variety of other probes. Moreover the ISH technique described does not require toxic denaturing agents, such as formamide.
Flavonoids from Apis mellifera Beeswax
Authors: Tomás-Barberán F. A. , Ferreres F. , Tomás-Lorente F. , Ortiz A.
Published: August 2018

The flavonoids present in beeswax produced in “La Alcarria” region were analyzed by HPLC. Pinocembrin, pinobanksin, pinobanksin 3-acetate, chrysin, galangin and techtochrysin were detected as the main flavonoid constituents. This is the first detailed report on the flavonoids of beeswax. These substances are already present when wax scales are secreted by bees. The same flavonoid compounds were generally present in honey, propolis and Populus nigra bud exudates collected in the same geographical region. These results indicate that beeswax flavonoids originate from those of honey and/or propolis, and suggest that analysis of beeswax flavonoids could be used as an adjunct in the detection of beeswax adulterations.
Cast Skin Lipids of the Indian Python (Python molurus bivittatus, Kühl, 1820)
Authors: Jacob Jürgen , Ziemsen Britt , Hoppe Udo
Published: August 2018

Cast skins of various snakes and in addition one lizard were found to contain 3.5-8.6% extractable lipid material. Lipids obtained from a cast skin of the Indian python were analyzed in detail indicating the presence of hydrocarbons (squalene, cholestadiene and alkanes), monoester waxes, sterol esters, diester waxes, triglycerides, sterols, free fatty acids and even more polar lipids. Among the monoester wax constituents odd-numbered secondary alkanols were found. It is assumed that the above lipids originate from cells of the past integumental generation and that they play an important facilitating role during the sloughing process.
Spectral Categories in the Learning Behaviour of Blowflies
Authors: Troje Nikolaus
Published: August 2018

Wavelength discrimination in the flower visiting blowfly Lucilia spec, was investigated in an attempt to elucidate the mechanisms underlying colour vision in this insect. The flies were subjected to a classical conditioning procedure in which they had to discriminate between a rewarded and an unrewarded monochromatic light stimulus. The results reveal large wavelength ranges within which no discrimination occurs, between which, however, a very distinct discrimination is found. The first range consists of the UV region up to 400 nm (UV). The second range comprises wavelengths between 400 nm and 515 nm (BLUE) and the third range all wavelengths longer than 515 nm (YELLOW). A simple model consisting of two colour opponent subsystems (R7p /R8p and R7y/R8y) can explain these results. Each of the two subsystems is assumed to evaluate only whether the sign of the difference between the excitations of R7 and R8 is positive or negative. For the whole system there are thus four possible conditions: p+y+, p+y-, p-y+, p-y-. Three of them correspond to the experimentally obtained wavelength ranges. The fourth condition (p+y-) might represent a still hypothetical PURPLE category in which the stimulus is made up of both short and long wavelengths.
Deoxyribonucleotide Synthesis in Phycovirus-Infected Green Algae. A New Virus-Induced Ribonucleotide Reductase
Authors: Bornemann Claus , Follmann Hartmut
Published: August 2018

Infection of Chlorella-like green algae with freshwater phycoviruses is associated with a large and rapid demand for DNA precursors which cannot be met by the algal deoxyribonucleotide-synthesizing enzymes. We have demonstrated in these cells an up to ten-fold increase of the key enzyme, ribonucleotide reductase, 1-2 h post infection. The enzyme activity has been partially enriched from cell extracts. In vitro, it differs from that of uninfected algae in three characteristic parameters, viz. eight-fold higher resistance to millimolar hydroxyurea concentrations, much higher optimum concentration of an allosteric effector nucleotide, thymidine triphosphate, and an unusually low temperature optimum at 20 °C. We conclude that the large DNA phycoviruses, like Herpes and pox viruses, code for their own specific ribonucleotide reductase.
Biochemical Activities of Propolis Extracts. II. Photodynamic Activities
Authors: Volpert Regina , Elstner Erich F.
Published: August 2018

Ethanolic and aqueous extracts of the “bee glue” Propolis exhibit antioxidative properties and are used as antiinflammatory drugs in folk medicine. In order to standardize the principle activities of prominent components of these extracts, simple biochemical tests have been introduced in the preceding paper. These activity tests prove the high antioxidative and inhibitory capacities of aqueous and ethanolic extracts of propolis in vitro. In the present communication we report on experiments documenting photodynamic quenching properties of these extracts. Using riboflavin, rose bengal or hematoporphyrin as photoactivators and ketomethyl-thiobutyric acid or crocin as indicators, the protective functions of propolis preparations can be demonstrated. The results indicate that the aqueous extracts are more active than the corresponding ethanolic preparation.
Differences between Thymic and Splenic Cells of the Rat: Biochemical and Physico-Chemical Investigations in vitro on DNA Topoisomerase II -Inhibitors and Thiyl Radicals
Authors: Tempel K.
Published: August 2018

Interactions of novobiocin (NB) and nalidixic acid (NA) with thiols were investigated in vitro in thymic (T-) and splenic (S-) cells of the rat, by determining nucleic acid synthesis as well as nucleoid sedimentation and viscosity of alkaline cell lysates. In T-cells NB, at concentrations of 0.35-1.4 mм, increased unscheduled D N A synthesis (UDS) and RNA synthesis (RNS), whereas S-cells underwent a dose-dependent inhibition of UDS and RNS following exposure to NB at concentrations > 0.7 mм. Combining NA and thiols (e.g., dithiothreitol) resulted in a slight stimulation of UDS in S-cells and in a highly significant increase of UDS in T-cells ascribed to a depletion of the cellular thymidine pool. In both cell types, neither NB nor NA exerted a significant effect on thiol-induced DNA damage. At a concentration of 1.4 mм, NB increased the viscosity of alkaline T-cell lysates; the opposite effect was observed in S-cells. From these results as well as from previous investigations we conclude that T-and S-cells differ in their state of chromatin conformation. This interpretation offers a simple model for the study of the influence of chromatin structure on cell-specific physico-and/or chemico-biologi-cal interactions.
Interactions of Halogenated Benzoquinones with the Non-Heme Iron (Q400) in Photosystem II
Authors: Koike Hiroyuki , Kashino Yasuhiro , Satoh Kazuhiko
Published: August 2018

Interactions of halogenated benzoquinones with the acceptor side of Photosystem (PS) II were studied by measuring fluorescence induction curves and flash-induced absorbance changes in PS II particles isolated from Synechococcus vulcanus. Following results were obtained: 1) Addition of some halogenated benzoquinones prior to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) in the dark increased the area above the fluorescence induction curve (work integral) by a factor of two. 2) Based on the ability to increase the fluorescence work integral, halogenated benzoquinones could be divided into two groups. 3) 2,6-Dichlorobenzo-quinone (2,6-DCBQ), trichlorobenzoquinone (TCBQ) and tetrahalogenated benzoquinones except tetrafluorobenzoquinone (fluoranil) (group A) increased the work integral, but 2,5-DCBQ and fluoranil (group B) did not. 4) Rapid reoxidation of QA
- was observed in the presence of quinones which belong to group A.

These results were interpreted in terms of dark oxidation of by quinones belonging to group A. Possible mechanisms of oxidation of Q400 by these quinones in the dark are discussed.
Isolation and Characterization of a Chlamydomonas reinhardtii Mutant Resistant to Photobleaching Herbicides
Authors: Oshio Hiromichi , Shibata Hideyuki , Mito Nobuaki , Yamamoto Masako , Harris Elizabeth H. , Gillham Nicholas W. , Boynton John E. , Sato Ryo
Published: August 2018

A group of highly active N -phenylimide photobleaching herbicides have been synthesized. These N -phenylimide herbicides as well as diphenyl ether herbicides induce protoporphyrin IX accumulation and inhibit protoporphyrinogen oxidase activity at extremely low concentrations in higher plants. The binding of a 14C -labeled N -phenylimide herbicide S-23121 [N-[4-chloro- 2-fluoro-5-[(1-m ethyl-2-propynyl)oxy]phenyl]-3,4,5,6-tetrahydrophthalimide] to the solubilized plastid fractions of greening corn seedlings is competed by the diphenyl ether herbicide acifluorfen-ethyl, but not by diuron, an inhibitor of photosynthetic electron transport. These results indicate a similar mode of action for both N -phenylimide and diphenyl ether herbicides.

In order to investigate the mechanism of photobleaching herbicides at the molecular level, a strain of Chlamydomonas reinhardtii RS-3 resistant to N -phenylimide S-23142 [N -(4-chloro- 2-fluoro-5-propargyloxyphenyl)-3,4,5,6-tetrahydrophthalimide] was isolated by mutagenesis with N -m ethyl-N′-nitro-N -nitrosoguanidine. The 90% inhibition concentration of N -phenylimide S-23142 for growth of RS-3 was 100 times higher than that for wild type. Maximum accumulation of protoporphyrin IX was reached at 0.03 μᴍ of S-23142 for the wild type and 3 μᴍ for RS-3. RS-3 was resistant to oxadiazon, oxyfluorfen and acifluorfen-ethyl which had been shown to have the same mechanism of action as N -phenylimide herbicides, but not to paraquat, diuron or fluridone. Genetic analysis of RS-3 strain showed that the resistance results from a dominant mutation ( rs-3) in the nuclear genome. The magnesium protoporphyrin IX synthesizing activity from 5-am inolevulinic acid in chloroplast fragments isolated from RS-3 was less sensitive to S-23142 than that from wild type (CC-407). Protoporphyrinogen oxidase activity in Percoll™ -purified chloroplasts from RS-3 was also less sensitive to S-23142 than that from wild type. These results indicate that the resistance of RS-3 is specific for photobleaching herbicides, and that the mutation is related to protoporphyrinogen oxidase, the primary site of the photobleaching herbicide action.
The Effect of Free Radical Enhancers and Scavengers on Accumulation of Early Light-Inducible Protein during Light Stress
Authors: Adamska Iwona , Kloppstech Klaus , Ohad Itzhak
Published: August 2018

Involvement of active oxygen species in the accumulation of early light-inducible protein (ELIP) in mature pea plants was investigated under light stress conditions. Here we provide evidence that hydroxyl radicals and singlet oxygen interfere with ELIP expression at both , transcriptional and posttranslational levels. Addition of free radical scavengers can alleviate the detrimental action of the radicals almost completely at the level of transcription but only a partial protection was observed at the level of proteins. The data suggest that the damage of ELIP occurs during its insertion into thylakoid membranes close to the free radical sources.
Energy Transfer from NADPH to Protochlorophyllide in Isolated Protochlorophyllide Holochrome as Determined by UV-Fluorescence Excitation Spectroscopy at 77 K
Authors: Lebedev Nikolai N. , Dujardin Ether
Published: August 2018

The low -temperature fluorescence excitation analysis of different protochlorophyllide (PChlide) forms has been extended to the UV part of the spectrum . A new band at about 360 nm was detected in excitation spectra of active PChlide forms bound to isolated protochlorophyllide holochrome. This band is very similar to the absorbance of NADPH in this region and its intensity depends on the redox state of the surrounding medium. On illumination at low temperature the intensity of the band decreases considerably with out any corresponding changes in the redox state of “ free” NADPH in the surrounding medium. A new intermediate state exhibiting a mixed excitation spectrum between PChlide and chlorophyllide (Chlide) was detected in the course of PChlide photoconversion.
Pseudoverdin, a Compound Related to the Pyoverdin Chromophore from a Pseudomonas aeruginosa Strain Incapable to Produce Pyoverdins [1]
Authors: Longerich Irmgard , Taraz Kambiz , Budzikiewicz Herber , Tsai Lin , Meyer Jean-Marie
Published: August 2018

From a genetically manipulated strain of Pseudomonas aeruginosa ATCC 15692 (PAO 1 strain) a compound named pseudoverdin, 3-formylamino-6,7-dihydroxycoumarin, was obtained which is related to the typical pyoverdin chromophore and thus allows to shed some light on the biogenesis of the latter.
Pheromone 93 [1]. Das Sexualpheromon von Limnaecia phragmitella (Lepidoptera: Cosmopterigidae) / Pheromones, 93 [1], The Sex Pheromone of the Cosmopterigid Moth Limnaecia phragmitella (Lepidoptera: Cosmopterigidae)
Authors: Bestmann Hans Jürgen , Kern Friedrich , Janssen Edelgard , Hasenfuß Ivar
Published: August 2018

By means of gas chromatographic, mass spectroscopic methods and combined GCelectroantennogram techniques (Z)-11-tetradecenyl acetate and (Z)-11-tetradecenyl acetate were identified as the two biological active components of the sex pheromone of the female cosmopterigid moth Limnaecia phragmitella. The mixture of 95% (Z)-11-tetradecenyl acetate and 5% of the (Z)-isomer were analyzed in the gland of females and confirmed as the most attractive synthetic blend for males in field bioassays.
Antioxidative Properties of Phenazone Derivatives: Differentiation between Phenylbutazon and Mofebutazon
Authors: Schneider Ingrid , Elstner Erich F.
Published: August 2018

Both phenylbutazon and mofebutazon inhibit oxidative fragmentation of the methionine derivative, 2-keto-4-methylthio-butyric acid (KMB) by xanthine oxidase - or diaphorase me­ diated OH radical production. Differentiation of the two non-steroidal antiinflammatory drugs is possible by means of determining oxygen reduction by xanthine oxidase or diaphorase in the presence of the naphthoquinone, juglone, where only mofebutazon shows an inhibitory effect.
Immunological Identification of Organ Specific Proteins and Transcripts in Developing Barley Grains
Authors: Klungland Helge , Bosnes Marie
Published: August 2018

In vitro translated proteins from poly(A+)RNA of immature barley starchy endosperm and embryos were immunoadsorbed with antibodies raised against proteins of aleurone layers, starchy endosperm and embryos. Four starchy endosperm and eight embryo specific transcripts were detected. In addition, several mRNA s were restricted to only two of the three tis­sues.

Comparing SDS-PAGE patterns of the in vivo protein extracts against which the antibodies were raised, four aleurone, six starchy endosperm and four embryo-specific protein bands were detectable. As for the in vitro translated proteins, several in vivo protein bands were here present in only two of the three tissues.

Of eight known barley grain proteins for which antibodies were available, only three were present in developing embryos.
Brominated Secondary Compounds from the Marine Sponge Verongia aerophoba and the Sponge Feeding Gastropod Tylodina perversa
Authors: Teeyapant Ratana , Kreis Patricia , Wray Victor , Witte Ludger , Proksch Peter
Published: August 2018

Analysis of the marine sponge Verongia aerophoba from the Canary islands afforded the brominated secondary constituents isofistularin-3, aerophobin-1 and aerophobin-2 which are probably involved in the chemical defense of the sponge. In addition the yellow pigment uranidine and the unusual sterol aplysterol were isolated. The patterns of brominated compounds were almost superimposable when samples of V. aerophoba from different islands were com­ pared by HPLC indicating de novo synthesis by the sponge or by endosymbiotic microorgan­isms rather than uptake by filter feeding. The only differences observed between the different samples analyzed were with regard to the total concentrations of brominated compounds which varied from 7.2-12.3% of the dry weight dependent on the different collection sites. The Opisthobranch gastropod Tylodina perversa is specialized for feeding on V. aerophoba. Chemical analysis of the gastropod revealed the sponge constituents uranidine, isofistularin-3, aerophobin-1 and aerophobin-2 as well as aerothionin, a further brominated compound which is apparently a biotransform ation product of the brominated sponge constiiuents.
Epicuticular Leaf Waxes of the Hop (Humulus lupulus). Chemical Composition and Surface Structures
Authors: Gülz P.-G. , Müller E. , Herrmann T. , Lösel P.
Published: August 2018

The epicuticular wax layer of Humulus lupulus contains homologous series of hydrocarbons, wax esters, benzylacyl esters, aldehydes, primary alcohols, fatty acids and the triterpenoids β-amyrin, α-amyrin both free and esterified with long chain fatty acids and also friedelanone. At 54%, primary alcohols form the largest component. No single class of lipids forms a pre­dominant component (i.e. more than 80%) of the wax layer. Under scanning microscopical examination, both upper and lower surfaces of H. lupulus leaves appear covered by a continuous way layer which is devoid of any sculpturing or crystalloids. Epidermal cells are arranged in dense lamellate or undulate cuticular folds. Four different types of trichomes were identified on the surfaces of hop leaves and tendrils. The adaxial leaf surface bears numerous single, uni­ cellular, silicified, pointed hairs as well as many glands. On the abaxial leaf surface there are very long pointed hairs arising only from the veins. Hairs on the hop tendrils arise from the veins but are completely different in shape having two sharp points extending at right angles to the hair-base.
Glandular Trichomes and the Yolatiles Obtained by Steam Distillation of Quercus robur Leaves
Authors: Engel Ralf , Gülz Paul-Gerhard , Herrmann Thorsten , Nahrstedt Adolf
Published: August 2018

Glandular trichomes in form of long stretched tubes are present on the lower leaf side of Quercus robur as shown by scanning electron microscopy. The glands contain an essential oil, which was isolated by steam distillation together with volatile waxy components of the leaves in an amount of 0.025% of fresh leaves. The product of steam distillation was analyzed by GC-MS. Identification of com pounds is based on comparison of their mass spectral data with those of authentic samples in combination with retention indices and MS data using the SeKoMS (Search Kovats Indices and Mass Spectra) Library. Altogether 184 components of the product of steam distillation were separated, 155 of which could be identified, another 7 were tentatively assigned. Three groups of substances according to their chemical composition are found: hexenyl derivatives and some acetals (32%); terpenes including monoterpenes (4% ), sesquiterpenes and diterpenes (21%); and alkane derivatives (35%). The residual 8% consist of benzyl alcohol, com pounds which stem from the degradation of carotenes, and miscellaneous constituents
Volatile Constituents of Propolis
Authors: Bankova V. , Christov R. , Popov S. , Pureb O. , Bocari G.
Published: August 2018

Volatile oils from Albanian, Bulgarian and Mongolian propolis have been investigated.
Biochemical Activities of Propolis-Extracts III. Inhibition of Dihydrofolate Reductase
Authors: Strehl Elke , Volpert Regina , Elstner Erich F.
Published: August 2018

Ethanolic and aqueous extracts of the natural compound PROPOLIS indicate substantial antiinflammatory functions as well as antibiotic activities in vitro and in vivo. The exact mode of physiological or biochemical mechanisms responsible for the medical effects, however, is all but clear. The standardization on the basis of quantitative determination of prominent components of these extracts have been substituted recently by simple biochemical model reactions including photodynamic properties. In this communication we report on the inhibitory activity of an aqueous extract of propolis on the enzyme dihydrofolate reductase. This activity may at least partially be due to the content of caffeic acid, as revealed by HPLC chromatography and comparative activity tests of representative ingredients of the propolis extract. This result may explain some of the protective functions of propolis, similar to those shown for several “non-steroidal antiinflammatory drugs”, NSAIDs.
Insecticidal and Fungicidal Compounds from Isatis tinctoria
Authors: Seifert K. , U nger W.
Published: August 2018

Tryptanthrin (1), indole-3-acetonitrile (2) and p-coumaric acid methylester (3) were isolated from the aerial parts of Isatis tinctoria L. The compounds show insecticidal and antifeedant activity against termites (Reticulitermis santonensis), insect preventive and control activity against larvae of the house longhorn beetle (Hylotrupes bajulus) and fungicidal activity against the brown-rot fungus (Coniophora puteana).
Isomerization and Peroxidizing Phytotoxicity of Thiadiazolidine Herbicides
Authors: Sato Y ukiharu , Hoshi Toshinobu , Iida Tetsuji , Ogino Chifuyu , Nicolaus Beate , Wakabayashi Ko , Böger Peter
Published: August 2018

Certain 5-(arylimino)-3,4-tetramethylene-1,3,4-thiadiazolidin-2-ones (thiadiazolidines) are peroxidizing bleaching herbicides which interrupt chlorophyll biosynthesis, inhibit the activity of protoporphyrinogen oxidase, lead to accumulation of protoporphyrin IX, and induce ethane formation in the light. The same effects are caused by their isomers, the 4-aryl-1,2-tetramethylene-l,2,4-triazolidin-3-one-5-thiones (triazolidines). Couples of thiadiazolidines and corresponding triazolidine isomers were synthesized. Thiadiazolidines with a 4-bromophenylimino, 4-chlorophenylimino, 4-chloro-2-methylphenylimino, 4-chloro- 2-fluorophenylimino, 4-chloro-2-fluoro-5-propargyloxyphenylimino and 4-chloro-2-fluoro- 5-isopropoxyphenylimino moiety were converted to the corresponding triazolidines both with Echinochloa seedlings or a spinach homogenate present, depending on the 5-arylimino moiety. The 5-[4-(chlorobenzyloxy)phenylimino]-3,4-tetramethylene-1,3,4-thiadiazolidin-2- one analogue did not convert to the corresponding triazolidine under both conditions. Thiadiazolidines as well as triazolidines having a 4-chloro-2-fluoro-5-methoxycarbonylmethylthiophenyl moiety were converted to an unidentified compound whose structure is assumed to be 4-(4-chloro-2-fluoro-5-carboxymethylthiophenyl)-1,2-tetramethylene-1,2,4- triazolidin-3-one-5-thione. Apparently, the general conversion mechanism is caused by enzymatic hydrolysis of thiadiazolidines to an unstable intermediate which rapidly and spontaneously changes to the corresponding triazolidine isomer.
The Impairment of the Nodulation Process, Induced by a Bradyrhizobium japonicum Exopolysaccharide Mutant is Determined by the Genotype of the Host Plant
Authors: Kosch Kerstin , Jacobi Andreas , Parniske Martin , Werner Dietrich , Müller Peter
Published: August 2018

The deletion mutant Bradyrhizobium japonicum ΔP22 produces a structurally altered exopolysaccharide. The nodulation of two cultivars each of Glycine max and Glycine soja, and cultivars of Macroptilium atropurpureum and Vigna radiata, infected with this mutant was examined in order to analyze the role of the exopolysaccharide in the infection process of plants with a determinate nodule type. All host plants analyzed exhibited delayed nodulation and formed fewer nodules per plant. The extent of the impairments depended on the genotype of the host plant. Morphological studies confirmed these results. In V radiata later steps in nodule development proceeded without further disturbances, whereas with G. soja PI 407287 minor changes were detected. In contrast, the inoculation of G. soja PI 468397 and M. atropurpureum lead to the formation of nodules most of which were not infected by Bradyrhizobium japonicum ΔP22 (Inf-). However, on M. atropurpureum at least some effective nitrogen-fixing nodules developed. Such nodules did not emerge from G. soja PI 468397. Inf- nodules were arrested in an early stage of nodule development, and symptoms of plant defense responses were observed.
Formation of 6'-Deoxychalcone 4'-Glucosides by Enzyme Extracts from Petals of Dahlia variabilis
Authors: Stich Karl , Halbwirth Heidrun , Wurst Friedrich , Forkmann Gert
Published: August 2018

Yellow colouration of Dahlia variabilis is mainly provided by isoliquiritigenin 4′-glucoside and butein 4′-glucoside. Incubation of petal extracts with uridin 5′-diphosphoglucose and isoliquiritigenin or butein led to the formation of one product which was identified as the respective 6′-deoxychalcone 4′-glucoside. Glucosylation of hydroxyl groups in other positions was not observed. Naringenin chalcone and eriodictyol chalcone were not accepted as substrates. The 4′-glucosylation of isoliquiritigenin and butein showed a broad pH optimum ranging from pH 7 to 8 and was stimulated by Mg2+, Ca2+ and Mn2+. N-Ethylmaleimide, p-hydroxymercuribenzoate, Cu2+, Zn2+, and Fe2+ clearly reduced the activity of the enzyme. The apparent Km values for UDP-glucose, isoliquiritigenin and butein were 90, 26 and 276 [μᴍ respectively.
Phenylalanine Analogues: Potent Inhibitors of Phenylalanine Ammonia-Lyase Are Weak Inhibitors of Phenylalanine-tRNA Synthetases
Authors: Metzger Gerhard Leubner , Amrhein Nikolaus
Published: August 2018

(1-Amino-2-phenylethyl)phosphonic acid (APEP), (1-amino-2-phenylethyl)phosphonous acid (APEPi), α-aminooxy-β-phenylpropionic acid (AOPP) and several other phenylalanine analogues are potent inhibitors of (S)-phenylalanine ammonia-lyase (PAL) in vitro and in vivo. The ability of these compounds to inhibit (S)-phenylalanine-tRNA synthetases (PRSs) from wheat germ, soybean, and baker’s yeast has been investigated and compared to the inhibition of PAL. APEP and APEPi were found to inhibit the tRNAphe-aminoacylation reactions catalyzed by the three PRSs studied in vitro in a competitive manner with respect to (5)-phenylalanine. (R)-APEP inhibits the PRSs with apparent Ki values of 144 μᴍ for wheat germ (app. Km for (S)-phe 5.2 μᴍ) , 130 μᴍ for soybean (app. Km for (S)-phe 0.9 μᴍ) , and 1096 μᴍ for baker’s yeast (app. Km for (S)-phe 5.5 μᴍ ) . The apparent Ki values for (R)-APEPi are 315 μᴍ , 160 μᴍ , and 117 μᴍ , respectively. APEP and APEPi inhibit the ATPpyrophosphate exchange reactions catalyzed by the PRSs from wheat germ and baker’s yeast, but they are not activated and do not serve as substrates in these reactions. AOPP has no affinity to any of the three PRSs, whereas it is a potent inhibitor of PAL. In light of our in vitro results with PRSs from different sources it appears unlikely that the PAL inhibitors we have studied have any significant inhibitory effect on this essential step in protein synthesis in vivo.
Simultaneous Gas-Exchange and Fluorescence Measurements with Ozone-Fumigated Spruce
Authors: Drenkard Stefan , Maguhn Jürgen , Knoppik Dietmar
Published: August 2018

A method was developed for carrying out gas-exchange and chlorophyll-fluorescence measurements simultaneously during fumigation of spruce twigs with peroxidic photooxidants. It is thus now possible to investigate how a pollutant affects distinct sectors of the photosynthetic apparatus of the plant: whereas fluorescence reveals any changes in the primary light reaction, CO2 gas-exchange measurements supply information about the biochemical reactions of the Calvin cycle. Results of short-time fumigation with 750 ppb ozone are presented here. Gas-exchange and fluorescence data are affected strongly in early summer, but not in autumn. The assimilation rate decreases significantly: primarily as a result of Rubisco activity and possibly because of direct inhibition of the electron-transport chain as well. Closure of the stomata leads to further reduction in the assimilation rate. Though no damage becomes visible on the needles, the perturbance of the photosynthetic apparatus caused by ozone fumigation is not reversible within 24 h.
Association of an Antibody-Conjugated Enzyme with Synthetic Polymers Dissolved in Organic Solvents
Authors: Kumakura M.
Published: August 2018

An antibody of a tumor marker (α-fetoprotein) conjugated with peroxidase was dispersed in organic solvents including synthetic polymers, and the interaction of the antibody with the polymers was investigated. It was found that the antibody-conjugated enzyme is associated with the polymers dissolved in hydrophobic organic solvents. The association correlated with the polymerization degree, concentration, and nature of the polymers.
Is There an Alternative Pathway for Starch Biosynthesis in Cereal Seeds?
Authors: Villand Per , Kleczkowski Leszek A.
Published: August 2018

A hypothesis is presented concerning a putative extra-am yloplastic location of barley seed endosperm ADP-glucose pyrophosphorylase (AGPase), a key enzyme of starch biosynthesis. The hypothesis is based both on indirect and direct evidence obtained in our laboratory as well as on data of other investigators. It is proposed that ADP-glucose form ed by the extraamyloplastic enzyme is transported to the am yloplasts via an ADP-glucose carrier in the plastid membrane, and then is utilized by the starch biosynthesizing machinery of these organelles. In addition to the extra-am yloplastic form of AGPase, barley endosperm contains also a second isozyme of AGPase, located in the amyloplasts. Presence of isozymes of AGPase in cereal seed endosperm is consistent with biochemical, molecular and genetic data on starch biosynthesis in this tissue
Partial Purification and Some Properties of Brassica napus Lipase
Authors: Fuchs Cornelia , Hansen Gerd
Published: August 2018

Lipase (triacylglycerol acylhydrolase EC 3.1.1.3) from rape (Brassica napus cv. Ceres) was isolated from cotyledons of dark-grown seedlings. The enzyme was partially purified by poly­ ethylene glycol precipitation. Delipidation of the lipase with n-hexane was required prior to further purification by anion exchange chromatography and size exclusion chromatography. A purification factor of 337 was ultimately achieved and the purification process was moni­tored by SDS-PAGE. Here, at least two protein bands with molecular masses of 62 and 64 kD a respectively were found in the active fraction obtained by size exclusion chromatography. Sodium deoxycholate was found to stimulate the lipase activity, but appeared to cause aggregation of the enzyme. It was not possible to estimate the isoelectric point of the dialyzed rape lipase due to the high molecular mass of the aggregates. Two simple methods to detect lipase activity directly on polyacrylamide gel were applied. No esterase activity was found by using p-nitrophenyl acetate as substrate.
Protective Role of Trehalose in Thermal Denaturation of Yeast Pyrophosphatase
Authors: Sola-Penna Mauro , Meyer-Fernandes José Roberto
Published: August 2018

Thermal Denaturation, Trehalose, Yeast Pyrophosphatase, Water Activity, Carbohydrates Trehalose, a disaccharide of glucose, is accumulated in yeast cytosol when this organism is submitted to a stress condition. Recently it was shown that the level of trehalose increase up to 15 times when yeast cells are submitted to heat shock (De Virgilio et al., 1991). In this report we give evidence how trehalose may play an important role on the stress-survival of yeasts when submitted to a heat shock. We show that 1.5 M trehalose increases 13-fold the half-time for thermal inactivation (t0.5) of yeast cytosolic pyrophosphatase at 50 °C. This thermal pro­tection conferred by trehalose is dose-dependent, after 10 min at 50 °C, a condition which inactivated pyrophosphatase, the presence of 2 M trehalose preserves 95% of total activity. Other carbohydrates were tested but were not so effective as trehalose. The presence of tre­halose at high concentrations in the reaction medium at 35 °C inhibits pyrophosphatase activity. This inhibition is less effective at 50 °C suggesting that under this condition the enzyme is temperature-protected and active.
Temporal Changes of the Lipid Peroxidation in Rats after Acute Intoxication by Ethanol
Authors: Charles Zdenek Zloch
Published: August 2018

received October 23, 1993/March 1, 1994 Ethanol, Microsomes, Mitochondria, Lipid Peroxidation, Hepatotoxicity A group of male rats were intoxicated within 24 h by three successive i.p. doses of ethyl alcohol (7.5 g per 1 kg of the body weight). In parallel, a control group of rats were dosed i.p. with a physiological saline. At time intervals of 0 h, 4 h, 24 h, and 48 h after the intoxi­ cation, the content of thiobarbiturate-reactive substances (TBARS) as product of lipid per­ oxidation within the liver and brain microsomes and mitochondria was followed.

In liver microsomes of the experimental rats there was a rapid increase (by 220%) in the content of TBARS during 4 h after the last application of ethanol, later on the level of lipid peroxidation decreased to the low original value. In other organelles examined only an insignificant increase in the content of TBARS was found. The results prove that an acute intoxication by ethanol does elicit an oxidative stress of the organism, expressed by a tran­siently increased production of TBARS. These oxidative and harmful changes for the cell structures are mostly located in the liver microsomes but a rapid repair of this damage fol­ lows. However, if such a short-term excessive abuse of alcohol is repeated more often, the above changes may lead to severe alcoholic injury
Gibberellins A19 and A24 from Yams, Dioscorea bulbifera, D. pentaphylla and D. oppositifolia
Authors: Tanno Nonaki , Nakayama Masayoshi , Yashima Hirofumi , Sunaga Kyoshi , Abe Mamoru , Okagami Nobuo , Yokota Takao
Published: August 2018

Gibberellin A19 (GA19) and GA24 were identified by gas chromatography-mass spectrometry from growing shoots of four strains of three species of D ioscorea, D. bulbifera var. vera, D. pentaphylla and D. oppositifolia (yams), which are distributed in the subtropical and tropical regions of Asia. An earlier report indicated the presence of several GAs including GA19 and GA24 in a cultivated temperate species of East Asia, D. opposita; these findings suggest possible coexistence of two GA biosynthetic pathways, early 13-hydroxylation and non-13-hydroxylation pathways comm only in Asian species of Dioscorea
A New Type of Antimicrobial Phenolics Produced by Plant Peroxidase and Its Possible Role in the Chemical Defense Systems against Plant Pathogens
Authors: Kobayashi Akio , Koguchi Yutaka , Kanzaki Hiroshi , Kajiyama Shin-ichiro , Kawazu Kazuyoshi
Published: August 2018

Syringaldehyde readily reacted in the horse-radish peroxidase (HRPOD) system. The ethyl acetate extract of the reaction mixture showed a marked antimicrobial activity against bacteria and fungi. After repeated column chromatography three potential antimicrobial compounds were obtained from the extract. The structural elucidation of active compounds was achieved by a combination of spectroscopic techniques and chemical modification
Phycoerythrin: Release from Cryptophycean Algae and Bilin Storage by the Primitive Metazoon Trichoplax adhaerens (Placozoa)
Authors: Wenderoth Heinz
Published: August 2018

Animal species that store bilins from external sources are very rare. A new example is described here. - Since the primitive marine metazoon Trichoplax adhaerens stains crimsonred when feeding on a phycoerythrin-containing alga. i.e. Pyrenomonas sp. (Cryptophyceae), the question arose whether an algal pigment can be identified as the staining matter. Thin layer chromatography and visible light absorption spectrography of aqueous Trichoplax extract disclosed several bilin components representing chromophores of phycoerythrin, a photosynthetic antenna protein that occurs only in certain algae and cyanobacteria. - Additional experiments showed that a cell-free Trichoplax extract kills and incompletely digests Pyrenomonas algae releasing phycoerythrin into the medium. These digestive faculties of Trichoplax tissue components, probably enzymes, contribute to the animal’s natural feeding mechanisms that proceed extra-as well as intracorporally. While the large apoprotein component of phycoerythrin is metabolized as a nutrient, the remaining chromophore bilins, strikingly coloured tetrapyrroles, are stored within Trichoplax’ distinct cellular inclusions, staining the animal crimson
Localization of the Pupal Melanization Reducing Factor of Inachis io (L.) and Comparison with Melanization and Reddish Coloration Hormone
Authors: Starnecker G. , Koch P. B. , Matsumoto S. , Mitsui T. , Bückmann D.
Published: August 2018

In Inachis io, a pupal melanization reducing factor (PMRF) which controls morphological color adaptation is located in the brain, suboesophageal ganglion, thoracic ganglia, and all abdominal ganglia. Higher PMRF amounts were extracted from abdominal ganglia than from the anterior ganglia. No PMRF activity could be found in the Corpora cardiaca-Corpora allata complex, in segmentally branching nerves of abdominal ganglia and their connectives.

Extracts from brain-thoracic ganglia and abdominal ganglia complex of I. io contained also a factor with melanization and reddish coloration hormone (MRCH) activity in Pseudaletia separata and with pheromone biosynthesis activating neuropeptide (PBAN) activity in Bom-byx mori. However, injection of synthetic Pseudaletia pheromonotropin (Pss-PT) (= Pss-MRCH) into prepupae of I. io did not yield a melanization reducing effect. Therefore, PMRF and the PBAN/MRCH related neuropeptides seem to be different molecules. The PBAN-like factor from I. io is possibly related to the myotropins and pyrokinins of insects
Diethyl Phosphate Binding to Mitochondrial Cardiolipin after Intraportal Infusion in Rats
Authors: Schole J. , Schole Chr. , Eikemeyer J.
Published: August 2018

20 min after intraportal infusion of diethyl phosphate (DEP) in rats, the mitochondrial cardiolipin (CL; 1,3-bisphosphatidyl glycerol) fraction is labelled with DEP. The obtained mixture of CL and DEP-labelled CL, which up to now has not been separated, behaves chromatographically (fractogel; HPLC; TLC), in respect to release of DEP and also in respect of the 31P NMR spectrum as a mixture of CL and cardiolipin ketone diethylenol phosphate. The latter compound was also obtained by photochemical reaction of CL ketone with diethyl phosphoric acid. After cautious hydrogenation (palladium charcoal) of the total mitochondrial lipid fraction of rats treated with DEP and subsequent extraction with NaCl solution (0.005 mol/1), glycerol-2-DEP has been identified in the water phase. It is supposed that this phosphoric acid derivative is formed from CL-DEP by elimination of two molecules of phosphatidic acid.
Kinetics and Regulation of the NAD(P)H-Dependent Glyoxylate-Specific Reductase from Spinach Leaves
Authors: Kleczkowski Leszek A.
Published: August 2018

Kinetic mechanism of purified spinach leaf NAD(P)H glyoxylate reductase (GR-1) was studied using either NADPH and NADH as alternative substrates with glyoxylate. The mech­anism was elucidated from substrate kinetic patterns using NADH as a cofactor rather than NADPH. With NADPH varied versus glyoxylate, and with NADPH and glyoxylate varied at a constant ratio, the patterns obtained on double reciprocal plots appeared to be consistent with a ping-pong mechanism; however, kinetic patterns with NADH conclusively ruled out the ping-pong reaction in favour of the sequential addition of the reactants. Product inhi­bition studies with glycolate and NADP have suggested either that NADPH binds to the enzyme before glyoxylate or that the addition of substrates is a random one. Studies with active group modifiers suggested an involvement of histidine, serine and cysteine residues in GR-1 activity. Salts had little or no effect on the activity of the enzyme, with the exception of cyanide, which had an apparent Ki of ca. 2 mᴍ. Studies with several metabolites used as possible effectors of GR-1 activity have suggested that the enzyme is modulated only by substrate availability in vivo. The apparent insensitivity of GR-1 to metabolic effectors is consistent with the proposed role of the enzyme in detoxifying glyoxylate which may act as a potent inhibitor of photosynthetic processes in plant tissues.
2,2-Dialkylacetic Acids -A New Class of Naturally Occurring Lipid Constituents
Authors: Raab Gottfried , Jacob Jürgen
Published: August 2018

The uropygial gland waxes of the South American red-legged Seriema (Cariama cristata (L., 1766)) were found to be composed of unbranched alcohols and 2,2′-dialkyl-substituted acetic acids which so far have not been found in skin lipids. When used as a chemosystematic character, the occurrence of this lipid class separates the order Cariamiformes (Seriemas) from all other avian orders hitherto investigated, especially from the Gruiformes (cranes and rails) to which they have been tentatively attributed in the past.

From the GC retention time data now available for a series of 2-alkyl-substituted fatty acid methyl esters relative retention time indices for other compounds may be predicted.
Evidence for a Cardenolide Carrier in Oncopeltus fasciatus (Dallas) (Insecta: Hemiptera)
Authors: Detzel Andreas , Wink Michael
Published: August 2018

Oncopeltus fasciatus (Hemiptera) is morphologically and physiologically adapted to seques­ter cardiac glycosides for its chemical defence against predators. As a prerequisite for carde­nolide utilization this bug has to take up and store the dietary cardenolides. Using isolated midguts it could be shown experimentally that the resorption of [3H]digoxin is time-, and temperature-dependent. The hydrogen ion concentration for uptake is optimal between pH 5.5 and 7 and an activation energy of 45 to 49 kJ/mol can be derived from an Arrhenius plot. Uptake can be inhibited competitively by the polar cardiac glycoside convallatoxin. Sulfhydryl group reagents (N-ethylmaleimide), membrane destabilizing compounds and respira­tory chain inhibitors reduce digoxin resorption, as do inhibitors of sugar transport (e.g., phloridzin). The experimental data thus provide evidence for a cardenolide carrier in midgut cells of O. fasciatus.