Volume 56, Issue 5-6

The paper gives an overview of literature on paraquat resistance of weeds and the proposed mechanism of resistance. New results we achieved on horseweed ( Conyza canadensis /L./, Cronq.) are discussed in detail. It was demonstrated that there is no significant constitutive difference related to the paraquat resistance between untreated susceptible and paraquat-resistant horseweed plants. The lower sensitivity of flowering resistant plants may be due to the fact that paraquat content in treated leaves of flowering resistant plants was only 25% as compared to those measured at rosette stage. Our results confirm that paraquat resistance is not based on elevated level and activity of antioxidant enzyme system. The hypothesized role of polyamines in the resistance mechanisms can be excluded. The higher putrescine and total polyamine content of paraquat treated resistant leaves can rather be regarded as a general stress response, than as a symptom of paraquat resistance. A paraquat-inducible protein is supposed to play a role in the resistance, which presumably functions by binding paraquat to an inactivating site and/ or by carrying paraquat to metabolically inactive cell compartment (vacuole, cell wall). From model experiments it is concluded that paraquat and diquat preferentially form hydrophylic interactions with proteins containing a higher amount of lysine and glutamic acid. Consequently, the reason for paraquat resistance in horseweed is probably a hydrophylic interaction of paraquat with a protein, leading to inactivation of paraquat through forming a conjugate and/or sequestration into the vacuole or the cell wall.

Two new lignan glycosides of dibenzylbutyrolactol type (haplomarin) and arylnaphthalene type (haploborin) were isolated from the aerial parts of Haplophyllum suaveolens together with the known arylnaphthalene lignan glycoside arabelline and hydroxycoumarin glycoside xeroboside. So far arabelline is found only in H. buxbaumii. This is the first report of the isolation of xeroboside from Haplophyllum.

In crude cell extracts of the ectomycorrhizal fungus, Suillus bovinus, activities of citrate synthase, aconitase, isocitrate dehydrogenase, succinate dehydrogenase, fumarase, and malate dehydrogenase have been proved and analyzed. Citrate synthase exhibited high affinities for both its substrates: oxaloacetate (K m = 0.018 mᴍ) and acetyl-CoA (K m = 0.014 mᴍ) . Aconitase showed better affinity for isocitrate (K m = 0.62 mᴍ) than for citrate (K m = 3.20 mᴍ) . Analysis of isocitrate dehydrogenase revealed only small maximum activity (60 nmol x mg protein -1 x min -1 ), the enzyme being exclusively NADP + -dependent. Using the artificial electron acceptor dichlorophenol indophenol, activity and substrate affinity of succinate dehydrogenase were rather poor. Fumarase proved Fe 2+ -independent. Its affinity for malate was found higher ( K m = 1.19 mᴍ) than that for fumarate ( K m = 2.09 mᴍ) . High total activity of malate dehydrogenase could be separated by native PAGE into a slowly running species of (mainly) cytosolic (about 80%) and a faster running species of (mainly) mitochondrial origin. Affinities for oxaloacetate of the two enzyme species were found identical within limits of significance (K m = 0.24 mᴍ and 0.22 mᴍ) . The assumed cytosolic enzyme exhibited affinity for malate (K m = 5.77 mᴍ) more than one order of magnitude lower than that for oxaloacetate. FPLC on superose 12 revealed only one activity band at a molecular mass of 100 ± 15 kDa. Activities of 2-oxoglutarate dehydrogenase and of succinyl-CoA synthetase could not be found. Technical problems in their detection, but also existence of an incomplete tricarboxylic acid cycle are considered. Metabolite affinities, maximum activities and pʜ-dependences of fumarase and of malate dehydrogenase allow the assumption of a reductive instead of oxidative function of these enzymes in vivo.

The extraction of red beetroot (Beta vulgaris) peel betalains and phenolics was compared with two extraction methods and solvents. The content of total phenolics in the extracts was determined according to a modification of the Folin-Ciocalteu method and expressed as gallic acid equivalents (GAE). The profiles of extracts were analysed by high-performance liquid chromatography (HPLC). The compounds of beetroot peel extracted with 80% aqueous methanol were characterised from separated fractions using HPLC- diode array detection (HPLC-DAD) and HPLC- electrospray ionisation-mass spectrometry (HPLC-ESI-MS) techniques. The extraction methods and the choice of solvent affected noticeably the content of individual compounds in the extract. The betalains found in beetroot peel extract were vulgaxanthin I, vulgaxanthin II, indicaxanthin, betanin, prebetanin, isobetanin and neobetanin. Also cyclodopa glucoside, N-formylcyclodopa glucoside, glucoside of dihydroxyindolcarboxylic acid, betalamic acid, ʟ-tryptophan, p-coumaric acid, ferulic acid and traces of unidentified flavonoids were detected.

Betacyanine and ionic leakage from red beet (Beta vulgaris ssp. L. rapacea) roots and lilac (Syringa vulgaris L.) leaves under the influence of new aminophosphonates were studied by spectroscopic and conductometric methods. It was found that the leakage of dye or electrolytes depended both on the concentration of the compounds used and their structural features. The results compared to those obtained for the well known herbicide Buminafos ® (dibutyl 1-butylamino-1-cyclohexanephosphonate) enabled to conclude that some of the compounds studied exhibited comparable or better activity than this herbicide. That makes them potentially good herbicides. It is possible that the effects observed are the result of action on cell membranes of the tissues used. The possible role of the structural features of aminophosphonates in this action is discussed.

As a part of our studies on the biologically active substances from Spanish plants, we have undertaken an investigation of the chemical constituents of a typical mediterranean species, Phillyrea latifolia L. (Oleaceae). Two secoiridoid glycosides, three phenylpropanoid glycosides, one lignane and two triterpenic acids were isolated from the leaves of this species and identified. The phytochemical analysis of the aerial parts of P. latifolia revealed that it is a rich source of oleuropeoside.

The terpenes, sterols, alkaloid (glaucine) and α-tocopherol show seasonal variation for Croton hemiargyreus hemiargyreus and Croton echinocarpus. The amounts of triterpenes are higher during the tropical summer and in most samples the major sesquiterpene was characterized as caryophyllene. The seasonal variation of glaucine showed a maximum between June and October for C. hemiargyreus, and was present only in January and June in C. echinocarpus.

Bacteriochlorophyll a has a maximum at 258 nm previously related to the ring E ester system interacting with the π-system of the macrocycle. In this work, we compared the effect of lauryldimethylamine-N-oxide (LDAO) and alkaline pH on both the near infrared and the ultraviolet region of the LHII spectrum from Ectothiorhodospira sp. While LDAO induces only a shift of the 850 nm band arising from the Qy transition of the bacteriochlorophyll a, alkaline pH also causes a concomitant and reversible 10-nm shift from 258 to 248 nm. Both shifts have similar apparent pKs (12.3 and 12.6, respectively). Interestingly, the presence of NaCl reduces these pKs values to 11.4 and 11.7.

The relationship between thylakoid membrane fluidity and the process of photoinhibition at room and low (4 °C) temperature was investigated. Two different membrane perturbing agents - cholesterol and benzylalcohol were applied to manipulate the fluidity of isolated pea thylakoids. The photochemical activity of photosystem I (PSI) and photosystem II (PSII), polarographically determined, were measured at high light intensity for different time of illumination at both temperatures. The exposure of cholesterol- and benzylalcohol-treated thylakoid membranes to high light intensities resulted in inhibition of both studied photochemical activities, being more pronounced for PSII compared to PSI. Time dependencies of inhibition of PSI and PSII electron transport rates for untreated and membranes with altered fluidity were determined at 20 °C and 4 °C. The effect is more pronounced for PSII activity during low-temperature photoinhibition. The data are discussed in terms of the determining role of physico-chemical properties of thylakoid membranes for the response of photosynthetic apparatus to light stress.

Transformed root cultures of Catalpa ovata were established following shoots infection with four agropine strains of Agrobacterium rhizogenes. Frequency of root formation was dependent on the bacterial strain and the presence of acetosyringone in the incubation medium. It is the first report concerning the possibility of transforming Catalpa ovata by A. rhizogenes. Both transformed and untransformed root cultures of C. ovata were studied for their growth and phenylethanoid glycoside production. As with the roots of intact plants, cis-and trans-verbascoside as well as martynoside were produced in transformed and untransformed root cultures of C. ovata. In hairy roots, total (cis + trans) verbascoside production could be stimulated up to three-fold of that of roots of 6-month-old plants grown in a greenhouse, by using an appropriate root line cultured in liquid 1 / 2 B5 Gamborg medium containing indole-3-butyric acid (0.1 mg/1) in the dark but not light conditions. Transformed and untransformed root cultures of C. ovata were also found to have 10 times higher martynoside production than roots of intact plants.

From the aerial parts of Gutierrezia microcephala (Asteraceae), four oxyflavones were isolated, namely 5,7,2′-trihydroxy-3,6,8,4′,5′-pentamethoxyflavone (1); 5,7,4′-trihydroxy-3,6,8-trimethoxyflavone (2); 5,7,2′,4′-tetrahydroxy-3,6,8,5′-tetramethoxyflavone (3); 5,2′-dihydroxy- 3,6,7,8,4′,5′-hexamethoxyflavone (4), and an ent-clerodane, bacchabolivic acid (5). Compounds 1-5, the synthetic methyl ester (6 ), n-hexane and MeOH extracts were evaluated against the fall armyworm (Spodoptera frugiperda). Gedunin, a known insect growth regulator isolated from Cedrela spp. was used as a positive control. When tested for activity on neonate larvae into the no-choice artificial diet bioassay, flavone (1), clerodane (5), its methyl ester (6), MeOH and n-hexane extracts caused significant larval mortality with MC 50 of 3.9, 10.7, 3.46. 7.95 and 7.5 ppm at 7 days, respectively, as well as growth reduction. They also increased the development time of surviving larvae and a significant delay in time to pupation and adult emergence. Acute toxicity against adults of S. frugiperda was also found, 5, 6 , gedunin and n-hexane extract had the most potent activity with LD 50 value of 6.59, 15.05, 10.78, and 12.79 ppm, respectively. In addition, MeOH, n-hexane extracts, 5, 6 and gedunin caused acetylcholinesterase inhibition with 93.7,100,90.2,62.0 and 100% at 50.0 ppm, respectively; whereas 1-4 exhibited only moderate inhibitory activity. Compounds 1,5 and 6 showed inhibitory activities comparable with gedunin. These compounds could be responsible of the insect growth inhibitory activity of this plant.

The objective of the present work was to compare the effects of groups of tin and lead organometallic compounds and their mixtures with amphiphilic quaternary ammonium salts (QAS) on the process of calcium ion desorption from lecithin liposome membranes, as dependent on the properties of the hydrophilic and hydrophobic parts of QAS. In the investigations the method of radioactive labels was applied. Synergism and antagonism in the action of both groups of compounds were found. The effectiveness of the cooperation depended more on chain length of QAS compounds than on the size and polarity of their hydrophobic parts. The most effective of all compounds studied was a the mixture of benzyldimethylammonium chloride in a mixture with tripropyltin. Since the rate of calcium desorption proved to be a good measure of efficacy of biologically active surfactants, it seems that the conclusions reached in this paper may be useful for choosing compounds which are able to decontaminate the environment polluted with heavy metals.

Some phospholipids (e.g. lecithin) form a system of electric dipoles on the membrane surface layer. In the case of lecithin the positive dipole charge is located on the choline and the negative one on the phosphoric molecule group. These dipoles are arranged almost parallel to the membrane surface. Taking the dipole membrane structure as a base for further investigations, a computer model of the electrostatic interaction between the dipole system and the ionic admixture was investigated. The model presumes hexagonal centered or a rectangular flat geometry of the 121 dipoles distribution. The dipoles may rotate freely around round the motionless symmetry axis perpendicular to the system surface. The initial state is given by fixing the geometry of the dipole matrix and ionic admixture distribution. Subsequently this system underwent a computer simulation which consisted of a calculation of resultant force moments acting on each dipole caused by other dipoles and ions. These force moments lead the system to the equilibrium state (minimum of the binding energy). The minimum energy value of the dipoles system depends on concentration and charge of the admixtured ions. The results of repeated simulations indicate that the system achieve the least of all binding energy (the most stable equilibrium state) at 1.5% concentration of admixtured ions in case of ion charge equal to 1Q (where Q denotes arbitrary unit of ion charge) and at 2.5% concentration of admixtured ions in case of ion charge equal to 2Q. The calculated results are in a good agreement with the experimental.

The micellization as well as the interaction with model membranes of dodecyltrimethylammonium halides (DTAX) and N-dodecyl-N,N-dimethyl-N-benzylammonium halides (DBeAX) were studied at 298K and 313K by means of titration calorimetry. The calorimetric curves reflect both the counterion and benzyl group effects on the interaction of the surfactants studied with the lipid bilayer. Bromide as counterion enhanced the interactions more than chloride of both DTAX and DBeAX compounds with model membranes. Further, we studied the influence of DTAX and DBeAX on calcium ion desorption from the liposome membrane using a radioactive tracer method. DBeAX proved more efficient in desorption of calcium than DTAX. Iodides of these compounds enhanced this process more than bromides and chlorides.

The conversion of δ-(ʟ-α-aminoadipyl)-ʟ-cysteinyl-ᴅ-valine (ACV) to isopenicillin N is dependant on the catalytic action of isopenicillin N - synthase (IPNS), an important enzyme in the penicillin and cephalosporin biosynthetic pathway. One of the amino acid residues suggested by the Aspergillus nidulans IPNS crystal structure for interaction with the valine isopropyl group of ACV is proline-283. Site-directed mutagenesis of the corresponding proline- 285 to leucine in Cephalosporium acremonium IPNS resulted in non-measurable activity but an increased soluble expression at higher temperatures in a heterologous E. coli host.

Penaeus monodon (class Crustacea, order Decapoda) is one of the largest shrimps of the Penaeidea family from the Indo - West Pacific region. The dioxygen-transporting protein hemocyanin, isolated from the hemolymph of this invertebrate, is composed of three 75 -76 kDa structural/functional subunits designated as Pm1, Pm2 and Pm3. The N-terminal sequences of the chains were determined and compared with those of other decapodan hemocyanin subunits. Pm2 and Pm3 are highly homologous and electrophoretically undistinguishable polypeptides. In comparison to Pm1, they have an extension of six residues. Pm1 is closely related to the subunit Pv2 of the Penaeus vannamei hemocyanin. Probably, subunits like Pm1 and Pv2 are family-specific for the Penaeidea hemocyanins and the other subunits are speciesspecific. Comparison of N-terminal sequences of respiratory proteins from the sub-orders Natantia and Reptantia demonstrated family- and sub-order-specific sequences. A melting point of 69 °C, lower than those for the di-hexameric decapodan hemocyanins, was determined from the temperature dependence of ellipticity of the mono-hexameric Penaeus monodon hemocyanin. Thermostability of decapodan hemocyanins depends on their aggregation state.

By means of thin-layer chromatography (TLC), electroantennogram (EAG), gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and field tests, (Z)-3-tetradecenyl acetate(Z3-14:Ac), (E)-3-tetradecen-1-ol(E3-14:OH), and (Z)-3-tetradecen-1-ol(Z3- 14:OH) at a ratio of 51:39:10 were identified from the female sex pheromone gland extracts of the carpenterworm, Holcocerus insularis Staudinger (Lepidoptera, Cossidae). The average amounts of Z3-14:Ac, E3-14:OH and Z3-14:OH in a single sex pheromone gland of calling moth were 7.29±2.72 ng, 5.72±2.43 ng and 1.44±0.56 ng, respectively. This is the first time that Z3-14:Ac was identified as a component of lepidopteran sex pheromone. Traps baited with rubber septa impregnated with Z3-14:Ac (500 μg / septum) were more effective than the traps baited with virgin female. The addition of the E3-14:OH and Z3-14:OH to rubber septa baited with Z3-14:Ac did not modify H. insularius male attraction, but E3-14:Ac slightly enhanced trap catch.

Labial gland secretions of 22 males of the bumblebee Bombus pomorum , collected in the Czech Republic, were analysed separately for each individual. The secretions contained 70 compounds among which saturated and unsaturated hydrocarbons strongly dominated. The proportion of hydrocarbons in the secretion was unusually high (85-100% ) compared to other bumblebee species studied so far (3-15%). Methyl and ethyl esters of fatty acids, known from many other bumblebee species, formed only minor components (less than 1 % in sum) of the secretions of several B. pomorum individuals. No terpenic compounds, typical for males’ marking secretion of many bumblebee species, were detected in B. pomorum . The absolute quantities of hydrocarbons present in the labial gland extracts were comparable with those usually present in other species. The composition of hydrocarbons found in the labial glands was different from the profile of the cuticular hydrocarbons. Despite our expectations in species exhibiting a regular patrolling and scent-marking behaviour, the labial gland extracts obtained from B. pom orum males were unusually low concentrated and their chemical composition was atypical with respect of the proportions of hydrocarbons when compared with other patrolling species. This is the first report on the analysis of the labial gland secretion of the B. pomorum males.

Growth hormone (G H ) promotes growth and endochondral ossification, but it is also important in the response to fasting due to its effects of increasing gluconeogenesis and lipolysis. In this study eleven raccoon dogs and blue foxes were followed for six months and their body mass and GH levels were measured. In November half of the animals of both species were put to a three-week fast. There were no significant differences in the GH levels between the animals of different ages and the subadults and adults both had quite low GH levels in the summer. Fasting had no effect on the GH levels of the raccoon dogs, but the fasting blue foxes had lower GH concentrations than the controls in Nov 16 th . The control blue foxes experienced a significant increase in the GH levels in early November and the fasting blue foxes in late November. The GH concentrations of all the raccoon dogs rose in early December. As fasting did not cause an elevation in the GH levels but the concentrations increased with decreasing temperature and shortening daylength, the autumnal GH secretion of these species could be regulated by endogenous seasonal rhythms entrained by exogenous Zeitgebers such as temperature or photoperiod. The autumnal increase of GH levels contributes to the response to fasting as an adaptation to survive the winter months with inadequate nutrition. The raccoon dog which spends the coldest part of the winter in winter sleep seems to be better adapted to a total fast than the actively wintering blue fox.

The antileishmanial and immunomodulatory potencies of a series of 28 polyphenols were evaluated in terms of extra- and intracellular leishmanicidal activity and macrophage activation for release of nitric oxide (NO), tumour necrosis factor (TNF) and interferon (IFN)- like properties. For this, several functional bioassays were employed including an in vitro model for leishmaniasis in which murine bone marrow-derived macrophages (BMMΦ) were infected with the obligate intracellular parasite Leishmania donovani, an extracellular Leishmania proliferation assay, a fibroblast-lysis assay (TNF-activity), and a biochemical assay for NO. Except for gallic acid, its methyl ester, shikimic acid and catechin (EC 50 25.8-67.9 nᴍ) all polyphenols tested significantly inhibited the intracellular survival of L. donovani amastigotes (EC 50 0.4 -13.9 nᴍ) when compared with the clinically used agent, sodium stibogluconate (EC 50 10.6 nᴍ). In contrast, none of the samples proved to be directly toxic for the extracellular promastigote form of the parasite. Noteworthy, the phenolic samples showed only moderate or no cytotoxicity against the murine host cells (EC 50 10 to >144 nᴍ). Although NO is an important effector molecule in macrophage microbicidal activity, the inducing potential of the test compounds for its release was found to be very moderate ranging from 7-54 μm (IFN-γ/LPS 119 μm). On the other hand, inhibition of NO production had no apparent effect on intracellular leishmanicidal activity of polyphenols. Their in vitro TNFinducing potential producing 50% lysis in murine L929 cells increased in the order of simple phenols and flavanols (34-48 U/ml) < A-type proanthocyanidins (53 -80 U/ml) < B-type proanthocyanidins (64-200 U/ml) < hydrolyzable tannins (287-350 U/ml) at the host cell subtoxic concentration of 50 μg/ml. Furthermore, gallic acid and some hydrolyzable tannins showed appreciable IFN-like activities ( 14-23 U/ml) as reflected by inhibition of the cytopathic effect of encephalomyocarditis virus on fibroblast L 929 cells. The results provide a rational basis for the recorded anti-infectious efficacy of traditionally used herbal medicines containing tannins in vivo, in the light of both only moderate direct antimicrobial activities of distinct polyphenols in vitro and the limited knowledge on their uptake in humans.

Expression of cyclooxygenase-2 (E. C. 1.14.99.1) in prostate and the lower urinary tract (LUT) of the neonatally estrogenized male rat has been studied by using a COX-2 ’s PCR fragment of 724 nt spanning 3 introns and a 478nt internal standard for quantitative RTPCR. The same fragment of 724 nt was used for RNA probe in Northern hybridization. Neonatal estrogenization (10 μg/day of diethylstilbestrol on days 1-5) had no effect on COX -2 expression in prostatic urethra, prostatic lobes, or bladder. Acute estrogen treatment of castrated animals did not induce COX-2 expression, either. In addition the differential expression of basal level of COX-2 in the different lobes of prostate in normal rat was demonstrated. Our results suggest a constant expression of COX-2 gene in prostate and the lower urinary tract of the neonatally estrogenized (neoDES) rats. The present study indicates that the increased expression of COX -2 is probably not essential for the estrogen-driven development of stromal inflammation or hyperplastic and dysplastic alterations in the prostate of neoDES rats.

A nonlinear, recurrent neural network model of the visual cortex is presented. Orientation maps emerge from adaptable afferent as well as plastic local intracortical circuits driven by random input stimuli. Lateral coupling structures self-organize into DOG profiles under the influence of pronounced emerging cortical activity blobs. The model’s simplified architecture and features are modeled to largely mimik neurobiological findings.

Onion cepa (L.) and Tsuga canadensis (L.) Carr, were investigated histochemically on the association of flavanols to nuclei. The young roots of Onion cepa are totally devoid of flavanol structures. Therefore, the excised roots tips were directly incubated into different solutions of flavanols. After 3 h of incubation a flavanol binding on the nuclei was recognizable, as seen by a yellowishbrown tanning reaction. Still to ensure the presence of flavanols on the nuclei, subsequent staining with the pdimethylaminocinnamaldehyde reagent (DMACA) resulted in an intense blue colouration. Tsuga canadensis has significant amounts of vacuolar flavanol deposits in all parts of the tree as indicated by the DMACA reagent. It is obvious that also the nuclei were associated strongly with flavanols which can be demonstrated particularly elegant in the cells of the seed wings by histochemical methods. However, the mode of flavanol release from the original deposits is not yet clear.