Showing papers in "Cellular and Molecular Life Sciences in 1983"

Cholinomimetics produce seizures and brain damage in rats

Abstract: Microinjections of the cholinergic agonists, carbachol and bethanechol, either into the amygdala or into the dorsal hippocampus produced sustained limbic seizures and brain damage in rats. Systemic administration of pilocarpine in rats resulted in a sequence of convulsive disorders and widespread brain damage as well. Scopolamine prevented the development of convulsive activity and brain damage produced by cholinomimetics. These results suggest that the excessive stimulation of cholinergic muscarinic receptors can lead to limbic seizures and brain damage. It is postulated that muscarinic cholinergic mechanisms are linked to the etiology of temporal lobe epilepsy and epileptic brain damage.

Metal complex formation by nicotianamine, a possible phytosiderophore

Abstract: The acid dissociation constants of nicotianamine (1) (pK1=6.97, pK2=9.13, pK3=9.75; 0.1 M KClO4, 25°C) and the stability constants for its 1∶1 complexes with bivalent metal ions (log KCu=18.6, log KNi=16.1, log KCo=14.8, log KZn=14.7, log KFe=12.1, log KMn=8.8, log KMg≈4.5; 0.1 M KClO4, 25°C) were determined using potentiometric titrations in aqueous solution. Fe(III)-nicotianamine complexes were not detected under the same experimental conditions.

Incorporation of xenobiotics into soil humus.

Abstract: The binding of pollutants to soil organic matter is a cause of some ecological concern. Many industrial and agricultural chemicals are structurally similar to humus constituents and, therefore, may be incorporated into soil organic matter during humification. Once bound to humus some pollutants are apparently detoxified. Several researchers have observed that the phytotoxicity of herbicides declines in soils which have a high organic matter content 92'97'99,114. Katan et al. 56 found that parathion residues in soil had no effect on fruit flies. However, it is not known if detoxication is permanent or temporary. Other studies indicate that xenobiotics bound to humic substances can later be released, thus posing a delayed health hazard. Microorganisms 52,66,79 and earthworms 34 can free these pollutants, which may subsequently be taken up by plants and agronomic crops33,34,49,63,113,116,118. In addition, the incorporation of man-made molecules into organic matter may affect soil structure and various physicochemical, microbiological and biochemical soil processes. Incorporated xenobiotics, also known as bound res i dues, are compounds foreign to soil which can not be extracted from humus by ordinary analytical methods. The term 'bound residue' is, to a large extent, defined by the extraction technique used. Since solvents vary in their extraction efficiencies, a xenobiotic which is inextractable using one method may be released when other solvents or reaction conditions are employed. As Kaufman has discussed in his introduction to a symposium on the subject, a precise definition of a bound residue is difficult to formulate 58. Incorporation into humus depends upon the type of xenobiotic introduced into soil and upon its subsequent transformation by microorganisms and abiotic factors. Certain man-made compounds are degraded to reactive intermediates (e.g., anilines and phenols) which are more likely to bind to soil organic matter than the parent chemicals. Binding may be catalyzed by microbial enzymes, some of which have been implicated in coupling reactions between pollutants and humus constituents 1~ 15, 17 Microbial populations can further influence incorporation by changing the physical or chemical environment of soil through their metabolic activities. Microbial metabolism can affect soil pH, redox conditions, oxygen content and many other factors. In addition, abiotic soil cornponents, such as metals and clays, seem to be important catalysts in the humification process 1~ 121. Xenobiotics are bound to humic substances by ionic or covalent bonding. They may also adsorb to humic substances by Van der Waals attractions, hydrogen bonding, charge transfer and hydrophobic bonding 62. The type of bonding which predominates is determined by the soil environment and by the chemical properties of the xenobiotic and the humus. In order to understand how xenobiotic-humus complexes are formed, it is necessary to briefly review the chemistry of humus and the process of humification?

The effect of methyl jasmonate on lycopene and β-carotene accumulation in ripening red tomatoes

Abstract: Methyl jasmonate at a concentration of 0.5% in lanolin paste was applied to detached mature green tomatoes cv. Venture. It caused the formation of a yellow colored epidermis and parenchyma at a depth of 2 mm on the place of treatment. Untreated areas, and areas treated with lanolin paste alone, developed a normal red color at the fully ripened stage. Analyses of carotenoid compositions showed that methyl jasmonate almost totally inhibited lycopene accumulation and stimulated β-carotene accumulation in the ripening of tomatoes.

Localization of substance P-immunoreactive nerve fibers in the human digital skin.

Abstract: Substance P-immunoreactive nerve endings were localized in human digital skin by the use of indirect immunohistochemical technique. It was found that substance P-like immunoreactivity was present in free nerve endings in the dermal papillae and in the epidermis. Some Meissner's corpuscles also contained substance P positive nerve endings. Furthermore, substance P-immunoreactive nerves were localized in close connection to sweat gland ducts and blood vessels. The functional significance of these findings was discussed with regard to pain mediation and inflammatory response.

Paracelsin, a peptide antibiotic containing alpha-aminoisobutyric acid, isolated from Trichoderma reesei Simmons. Part A.

Abstract: A peptide antibiotic has been isolated from Trichoderma reesei QM 9414. Although crystalline and uniform in TLC, this antibiotic could be resolved by HPLC into 3 sequence analogues. The close relationship to alamethicin was proved by chemical and spectroscopic methods, and the formation of ion-conducting pores in lipid bilayers.

Inhibition of host phenoloxidase activity by parasitoid Hymenoptera

Abstract: Partial or complete inhibition of hemolymph phenoloxidase activity occurred in host species attacked by some parasitoid wasps. In one system, inhibition of enzyme activity could be achieved by injection of a virus purified from parasitoid ovaries.

Ascidian sperm chymotrypsin-like enzyme; participation in fertilization.

Abstract: The action of a chymotrypsin-like enzyme from sperm extract from the ascidianHalocynthia roretzi was studied using several substrates. It was found that the most susceptible substrate had the most powerful inhibitory effect on fertilization in this animal. Among the substrates, the order of susceptibility coincided with the order of inhibitory ability, which indicates that the enzyme is involved in the fertilization process.

DNA polymerases in prokaryotes and eukaryotes: Mode of action and biological implications

Abstract: DNA transactions such as replication, repair and recombination require the concerted action of many proteins either alone or in a complex 1. Nevertheless, in all these processes one protein, the DNA polymerase, plays a central role. Its function is to ensure the accurate incorporation of the 4 deoxyribonucleoside triphosphates (dATP, dCTP, dGTP and dTTP) on a mother template according to the Watson-Crick base pairing rules (A to T and G to C). Since the discovery of the first DNA polymerase about 25 years ago 2 such enzymes have been found in all prokaryotic and eukaryotic organisms testedl,3-15,162,163. Although they differ in chemical, physical or immunological properties they all share the following important similarities: a) they incorporate a complementary deoxyribonucleoside triphosphate as monophosphate on a template by hydrolyzing the a-fl phosphodiester bond in the presence of cofactors (divalent cation and DNA), b) they all need a short complementary piece of nucleic acid (DNA or RNA), called primer, with a free hydroxyl group at the third carbon position of the (deoxy)-ribose to attach the first nucleotide and c) they all cause polymerisation in the 5' to 3' direction of the growing daughter strand. It is the aim of this review to compare DNA polymerases from prokaryotes and eukaryotes and especially to point out similarities and differences. In particular, attempts are made to compare Escherichia coli DNA polymerases I, II and Ill 1 with the different vertebrate DNA polymerases a, fl and v l6. Basic rules of DNA synthesis have been described for prokaryotic and eukaryotic cells and organisms 1. These include, e.g., semiconservative mode of replication, RNA priming, direction of replication, leading and lagging strand replication, excision repair processes. It seems that this extends to the DNA polymerase level since growing proand eukaryotic cells possess at least three different DNA polymerases 1, 3-16,162,163 Biological functions of the different DNA polymerases have been well studied in prokaryotes because of their genetics (conditional lethal mutants of certain DNA polymerase genes), and the ease of obtaining large cell quantities due to the short generation time of bacteria. On the other hand only indirect in vitro experimental evidence is available so far for the involvement of the mammalian DNA polymerases in replication and /or repair. Such descriptive results will always be tentative until conditional lethal DNA polymerase mutants are found. However, there have been reports of mutants in structural genes of DNA polymerases of lower eukaryotic cells, such as fungus and fruit-fly 17,18, indicating a direct involvement of these enzymes in chromosomal DNA replication. The DNA polymerase(s) involved in a particular DNA replication process is/are most likely to act in a complex with other proteins (factors) and enzymes, called the replisome 19. Similar concerted actions can also be postulated for DNA repair 2~ or DNA recombination 21. In DNA replication the multipolypeptide complex responsible for the overall DNA polymerization is henceforth called the DNA elongation complex or DNA elongation apparatus. In recent years a number of laboratories have described complexes of

The locus coeruleus: actions of psychoactive drugs.

Abstract: The locus coeruleus is one of the most thoroughly investigated mammalian brain areas. Its fibers innervate large parts of the neuraxis, in particular, areas involved in cognitive functions such as the cortex and the hippocampus. A role of locus coeruleus has been proposed in such processes as memory, the control of vigilance, blood pressure and others. Results obtained in this and other laboratories demonstrate that the firing rate of locus coeruleus neurons is affected by a great number of psychoactive agents such as antidepressants, minor tranquillizers, neuroleptics, psychostimulants and certain psychogeriatric drugs. We have attempted to correlate the data obtained on the cell bodies of locus coeruleus with studies reporting effects on terminal areas and thereby gain an overall view of the action of the above mentioned drugs on this cell system. The activity of noradrenergic neurons in locus coeruleus is thought to correlate with the level of cortical vigilance. Special emphasis is placed on the finding that a number of drugs which exert a positive effect on cognitive functions in man and animals increase the firing rate of the rat locus coeruleus neurons.

Evidence to support the hypothesis that ATP is a co-transmitter in rat vas deferens

Abstract: Application of exogenous ATP or of noradrenaline (NA) produced responses in bisected rat vas deferens which mimicked the biphasic responses to nerve stimulation, and these actions were modified by nifedipine and verapamil in a manner similar to the modification of the 2 phases of the responses of the vas to nerve stimulation. It is proposed that sufficient evidence now exists to support the hypothesis that in this tissue, ATP is released along with NA from the motor nerves and that ATP may indeed be a co-transmitter.

Bacterial growth on 1,2-dichloroethane

Abstract: 1,2-Dichloroethane (5 mM) served as the only carbon and energy source for bacterium DE2, a gram-negative, oxidase-positive, motile rod. The specific growth rate mu of strain DE2 on 1,2-dichloroethane was 0.08 h-1. A NAD-dependent 2-chloroacetaldehyde dehydrogenase activity and a 2-chloroacetate halidohydrolase activity were detected in extracts of cells grown on 1,2-dichloroethane.

Hypergravity promotes cell proliferation.

Abstract: When HeLa cells, chicken embryo fibroblasts, sarcoma Galliera cells, Friend leukemia virus transformed cells and human lymphocytes are cultured in a hypergravitational field (e.g. 10×g) proliferation rate is increased by 20–30%, whereas glucose consumption per cell is lower than at 1×g. Tracking of cell movements on gold-coated substrates reveals that cell migration is hindered at high-g. These findings suggest that under gravitational stress the cell is either capable of shifting to other metabolic pathways and/or consumes less energy at high-g than at 1×g. This work describes ground-based investigations related to experiments to be performed on future Spacelab missions.

Microbial degradation of synthetic organochlorine compounds.

Abstract: Although pesticides are designed to be selective, that is, more toxic to harmful organisms than to man and beneficial organisms, their selectivity is not always complete. Most pesticides are degraded chemically and biologically in nature. Their chemical degradation in water and soil is influenced by several factors such as pH, temperature, sunlight, moisture and coexisting inorganic and organic compounds. Examples of organochlorine compounds that have been used as pesticides are shown in figure 1. Because of their persistence in the environment, the use of organochlorine pesticides has been minimized in developed countries. For four decades, 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) and its derivatives have been widely used as herbicides, especially for the control of brush, jungle and aquatic weeds. The 1968 annual production of these compounds exceeded 60 million pounds in USA 5~ and residues of the substances have been detected in crops, soil, the atmosphere, rainwater and surface water. Technical 2,4,5-T contains traces of the highly toxic compound 2,3,7,8-terachlorodibenzo-pdioxin (TCDD) as an impurity 2. In addition, about 0.0002% of 2,4,5-T is converted to TCDD when wood or brush containing 2,4,5-T is burned. The spraying of the herbicide Orange (butyl esters of 2,4-D and 2,4,5-T in an equal amount) over jungle in Southeast Asia has resulted in the accumulation of TCDD in soil at a mean level of 1.9 ppm with maximum levels of 47 ppm. Pollution by TCDD has developed into a cause of continuing public anxiety throughout the world t~ As summarized in two recent reviews ]4,28, the toxity of organochlorine pesticides and their effects on microorganisms have been studied extensively. Organochlorine compounds used in industry and as pesticides are often found in drinking water. Approximately 80 different organic halogen compounds have been demonstrated in drinking water in the United States 49. Several of these are listed in table 1. Trihalomethanes such as bromodichloromethane, chlorodibromomethane and chloroform, which have been demonstrated ubiquitously in chlorinated water and which are suspected as carcinogens 13, are found even in drinking water. Chlorination of water is used widely for disinfecting water since it is the most effective method for killing waterborne pathogens

Adenosine activates a potassium conductance in guinea-pig atrial heart muscle

Abstract: Adenosine shortens the action potential and diminishes the force of contraction in guinea-pig left atria. These effects may be brought about by the activation of a potassium conductance. This assumption is supported by voltage clamp and42K release experiments.

Inhibition of erythrocyte ATPase activity by aclacinomycin and reverse effects of ascorbate on ATPase activity

Abstract: We studied the effect of aclacinomycin on human erythrocyte membrane enzymes. Aclacinomycin inhibited ATPase, including Na−K-dependent ATPase, ouabain insensitive ATPase and Ca-ATPase. However acetylcholinesterase was not inhibited by aclacinomycin. The ATPase activities were not inhibited by aclacinomycin if ascorbate was added to the incubation mixture. However other reducing agents, α-tocopherol, superoxide dismutase and catalase had no effect on ATPase activity. Ascorbate may protect membrane proteins and lipids from peroxidate damage.

Genetic aspects of biodegradation by pseudomonads.

Abstract: Microorganisms that are isolated on the basis of their ability to degrade natural or man-made organic substrates very often belong to the genus Pseudomonas. This may be because the pseudomonads have an extraordinary range of catabolic pathways, are easy to handle under laboratory conditions and generally grow on defined synthetic media. A single species such as P. cepacia utilizes more than 100 different substrates (out of 146 compounds tested) as the only C, N, or S source 22,98. Many recalcitrant chemicals (e.g., aromatics, chlorinated aliphatic compounds, pesticides) can be degraded by different Pseudomonas species or related soil bacteria isolated from nature. It is therefore pertinent to discuss the genetic organization of biodegradation functions in those Pseudomonas species that have been examined in some detail by genetic techniques. In addition, numerous methods that are potentially applicable to the study of biodegradation have been developed for Agrobacterium and Rhizobium genetics and some of these will be mentioned. Several reviews have been published describing the catabolic potential 22, the degradative plasmids 14,36 and chromosome maps 48 of Pseudomonas as well as the manipulation of soil bacteria by genetic engineering techniques 2, 36, 91. Microbial communities and cometabolism of organic substrates undoubtedly play an important role in nature 97. The geneticists, however, tend to shy away from such complex systems. They prefer pure cultures of distinct species and well-defined medium conditions allowing the selection of particular phenotypes. In the case of biodegradation pathways this means that a growth substrate should be utilized as the only C, N, S or P source. Occasionally, the disappearance of a colored substrate or the formation of a colored product may be helpful to monitor catabolic functions. Bacteria should grow on agar plates some strains with interesting biodegradation properties refuse to do that and allow at least one type of genetic transfer: conjugation, transduction, or transformation. The genetic analysis of bacteria used to be confined to members of the same or closely related species. In recent years, however, the scope of genetic research has greatly widened due to 3 major developments: a) Broad-host-range plasmids have been found that can replicate in virtually any gram-negative bacterium and enable the transfer of genetic information across the species barriers. b) The properties of transposons and other insertion elements may be used to produce insertion mutations and deletions, and mutated genes carrying a transposon insert may subsequently be isolated by recombinant DNA techniques. c) The gene cloning methods are universal in that the DNA from practically any organism can be inserted into cloning vectors. Several plasmid vectors that can be used in Pseudomonas species have been derived from broad-host-range plasmids.

Subcellular distribution and binding of heavy metals in the untreated liver of the squid; comparison with data from the livers of cadmium and silver-exposed rats.

Abstract: In natural squid liver, about 30% of the total Cd present was found in the cytosolic fraction. A large portion of this Cd was bound to high molecular weight species (mol. wt>70,000). In contrast to Cd, about 60% of the total Ag occurred in the cytosolic fraction; Ag was bound mainly to low molecular weight species (mol. wt<20,000).

Dietary carotenoids block photocarcinogenic enhancement by benzo (a)pyrene and inhibit its carcinogenesis in the dark

Abstract: The carotenoids beta-carotene (C) and canthaxanthine (CX), with and without pro-vitamin A activity, respectively, when perorally administered to mice, markedly prevent benzo(a)pyrene photocarcinogenic enhancement (BP-PCE), continue to block such BP-PCE and protect significantly against BP carcinogenesis in mice maintained in the dark These results appear relevant to both the pathogenesis of chemical carcinogenesis and rational programs of skin cancer prevention in humans

The site of action of La3+ in the reaction cycle of the human red cell membrane Ca2+-pump ATPase.

Abstract: Lanthanum (La3+) inhibits the Ca-pump of the red cell by arresting the protein in a phosphorylated form (PI). Similar La3+ concentrations are required to increase the amount of PI and to stop PI-decay. In the presence of La3+ phosphorylation becomes insensitive to Mg2+. PI made in the presence of Mg2+ is not prevented from decaying by subsequent addition of La3+, whereas that made in the absence of Mg2+ is. Taken together, these findings seem to indicate that La3+ blocks the transition between a 1st and a 2nd form of PI.

Species-specificity of paragonial substances as an isolating mechanism inDrosophila

Abstract: In 2 closely-related species ofDrosophila, the oviposition stimulating effects of the substances produced in the male accessory glands (paragonia) are species-specific. A unique reproductive isolating mechanism due to this specificity is discovered.

Difference in the absorption coefficient of enantiomers for arbitrarily polarized light in a magnetic field: A possible source of chirality in molecular evolution

Abstract: It is predicted that a static magnetic field parallel to the direction of propagation of an incident light beam causes a small shift in the value of the absorption coefficient of a chiral molecule. This shift is not a circular differential effect. It should occur with arbitrarily polarized light. However, for enantiomers, the sign of the shift is opposite. This effect, though relatively small, may lie at the origin of a mechanism by which, in early stages of molecular evolution and starting from a particular racemic mixture, a change in the relative concentration of the two enantiomers was induced, without the prerequisite of an asymmetric material environment or of an external source of circularly polarized light.

Isolation and cultivation of microbes with biodegradative potential

Abstract: 57 Mortlock, R.P., Metabolic acquisitions through laboratory selection. A. Rev. Microbiol. 36 (1982) 259-284. 58 Motosugi, K., and Soda, K., Microbial degradation of synthetic organochlorine compounds. Experientia 39 (1983) 1214-1220. 59 Omori, T., and Alexander, M., Bacterial and spontaneous dehalogenation of organic compounds. Appl. environ. Microbiol. 35 (1978) 512-516. 60 Patterson, J.W., and Kodukala, P.S., Biodegradation o f . . . Chem. Engng Progr, April (1981) 48-55. 61 Pearson, C.R., C1and C2 halocarbons, in: The handbo6k of environmental chemistry, vol. 3, p. 69. Ed. O. Hutzinger. Springer Verlag, Berlin 1982. 62 Philippi, M., Schmid, J., Wipf, H.K., and Ht~tter, R., A. microbial metabolite of TCDD. Experientia 38 (1982) 659-661. 63 Schweizerische Unfall-Versicherungs-Anstalt (SUVA). MAKWerte (1983). 64 Senior, E., Bull, A.T., and Slater, J.H., Enzyme evolution in a microbial community growing on the herbicide Dalapon. Nature 263 (1976) 476-479. 65 Stirling, D.I., and Dalton, H., The fortuitous oxidation and cometabolism of various carbon compounds by whole-cell suspensions of Methylococcus capsulatus (Bath). FEMS Microbiol. Lett. 5 (1979) 315-318. 66 Stirling, D.I., and Dalton, H., Oxidation of dimethyt ether, methyl formate and bromoethane by Methylococcus capsulatus (Bath). J. gen. Microbiol. 116 (1980) 277-283. 67 Stucki, G., Brunner, W., Staub, D., and Leisinger, T., Microbial degradation of chlorinated C1and C2 hydrocarbons, in: Microbial degradation of xenobiotics and recalcitrant compounds, pp. 131-137. Eds T. Leisinger, A.M. Cook, R. Ht~tter and J. Nt~esch. Academic Press, New York 1981. 68 Stucki, G., Galli, R., Ebersold, H.R., and Leisinger, T., Dehalogenation of dichloromethane by cell extracts of Hyphomicrobium DM2. Archs Microbiol. 130 (1981) 366 371. 1191

Western Palearctic water frogs (Amphibia, Ranidae): Systematics, genetics and population compositions

Abstract: Recent studies of the western Palearctic water frogs revealed the occurrence of at least 5 types of water frogs (Rana ridibunda, R. lessonae, R. perezi, 1 Italian and 1 Balkan species) as well as 4 types of their hybrids. In addition to the systematics, genetics and population compositions of these frogs, the complex mechanisms that lead to the production of the hybridogenetic hybridRana esculenta are emphasized, and the unsolved problems relating to the control of the hybridogenetic process are discussed.

Potential toxins of acute liver failure and their effects on blood-brain barrier permeability.

Abstract: The effects of potential toxins of hepatic coma on the blood-brain barrier (BBB) permeability of the rat have been examined using the Oldendorf technique. Classical toxins of hepatic failure such as ammonia, methyl octanoate, mercaptans, and phenol caused significant increases in BBB permeability. A slight increase in permeability occurred following infusion of peroxidized linoleic acid and unconjugated bilirubin but no increase after infusion of bile acids.E. coli endotoxin infused into rats following partial hepatectomy also increased the BBB permeability.

Juvenile hormone levels, vitellogenin and ovarian development inAcheta domesticus

Abstract: Juvenile hormone hemolymph titres have been determined by radioimmunoassay at the beginning of imaginal life in the cricketAcheta domesticus. JH III levels increased during previtellogenesis and at the onset of vitellogenesis in the successive waves of ovocytes. Vitellogenin synthesis started between the 24th and 40th h of imaginal life after bursts of juvenile hormone production and before any ecdysteroid had appeared in either the hemolymph or the ovaries.

Control of corpus allatum activity in Diploptera punctata : roles of the pars intercerebralis and pars lateralis

Abstract: Control of the corpora allata (CA) ofDiploptera punctata is maintained by at least 2 factors. The glands are directly inhibited by an allatostatin arriving at the CA via the nervi corporis cardiaci I (NCC I). Destruction of the putative source (median neurosecretory cells, MNC) of the allatostatin by radio-frequency (RF) cautery relieved the inhibition imposed on the CA of virgin females, and the glands became active. Similarly, destruction of the lateral neurosecretory cells (LNC) also relieved the inhibition. We propose that the LNC stimulated the MNC to release allatostatin. RF-cautery did not result in the activation of CA of pregnant or ovariectomized females. Activation of the CA may therefore require not only absence of the inhibitory factor but also the presence of a stimulatory one (perhaps from the ovary).

The intrapulmonary neuroepithelial bodies after vagotomy: demonstration of their sensory neuroreceptor-like innervation

Abstract: In the neonatal rabbit, infranodosal vagotomy destroys most of the intracorpuscular nerve endings of the pulmonary neuroepithelial bodies (NEB), while supranodosal vagotomy leaves these nerve endings intact. We conclude that NEB are mainly innervated by sensory neurons whose cell bodies lie in the nodose ganglion of the vagus nerve. These findings support the hypothesis that although secretory in nature, NEB are neuroreceptor structures.