Effects of insecticides on cultures of insect cells

Serial dilutions of 20 insecticides were examined for their effects on the growth of insect cells cultivated in vitro. No differences in susceptibility were found for cells derived from the moth Antheraea eucalypti and the mosquito Aedes aegypti.Rotenone was the most effective inhibitor investigated, decreasing the rate of cell division at 0.001 g/ml. Malathion and diazinon first showed effects at 12 g and 112/ml respectively. Toxicants first effective at 10 g/ml included pp-DDT, dieldrin, pyrethrins and sodium arsenate; at 100 g/ml they included lindane and carbaryl; at 1000 g/ml only nicotine sulphate.The majority of insecticides tested (principal exception rotenone) were very much more toxic to last instar A. aegypti larvae than to the insect cells, suggesting that the functions of highly organized tissues are more readily interfered with than those of individual cell types comprising them.

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Zusammenfassung Verdünnungsserien von 20 Insektiziden wurden auf ihren Effekt auf das Wachstum von in vitro kultivierten Insektenzellen untersucht. Die untersuchten Zellen stammten aus Kulturen von Ovariolen von Antheraea eucalypti-Puppen und von Gewebe von Aedes aegypti-Larven. Rotenon erwies sich als das wirksamste Insektizid: es verlangsamte die Zellteilung in einer Konzentration von 0.001 g/ml. Malathion wurde erst in einer Konzentration von 12 g/ml wirksam, Diazinon bei 112 g/ml. Mehrere Insektizide zeigten erste Wirksamkeit bei 10 g/ml; diese waren: pp-DDT, pp-DDD, pp-DDE, Methoxychlor, Aldrin, Dieldrin, Pyrethrine, Allethrin und Natriumarsenat. Insektizide mit einer ersten Wirksamkeit bei 100 g/ml waren Lindan, Isolan, Dimetilan, Carbaryl, DNOC und Piperonylbutoxid. Nikotinsulfat war erst bei 1 mg/ml oder bei höheren Konzentrationen wirksam. Zwischen den Antheraea- und Aedes-Zellen wurde kein Unterschied in der Empfindlichkeit gegen die verschiedenen Insektizide gefunden. Bei niedrigen Konzentrationen zeigten Malathion und Natriumarsenat erst nach dem 4. Tag bedeutendere Effekte. Ein schwacher synergistischer Effekt wurde beim Mischen von Pyrethrinen mit Piperonylbutoxid in niedrigen Konzentrationen beobachtet, nicht aber bei hohen Konzentrationen.Bei der Mehrzahl (17 von 19) der Insektizide waren die Zellen in 10 bis 10.000 mal höheren Insektizid-Konzentrationen zu überleben fähig als A. aegypti-Larven im letzten Stadium. Rotenon war das einzige Insektizid, dessen Toxizität auf Zellen stärker war (10.000 Mal) als auf intakte Larven.

     

Biological remediation of anthracene-contaminated soil in rotating bioreactors

Soil impregnated with anthracene was subjected to bacterial treatment as a model for remediation of soils contaminated with polycyclic aromatic hydrocarbons (PAHs). Roller bottles were used to simulate the mixing of solids in rotating drums. The soil was prepared as a 60 weight % slurry in salts medium, and inoculated with a mixed culture, selected for the ability to mineralize anthracene as its sole carbon source. The degradation of anthracene followed zero-order kinetics when it was well dispersed on the soil particles, consistent with a rate limitation by dissolution of solid hydrocarbon. Maximum degradation rates of 300 g/g per day were achieved in repeated batch operation, using a 10% volume of soil slurry as the inoculum for the succeeding batch. Anthracene degradation activity was maintained through 18 such transfers on a 3- to 4-day cycle. The culture produced soluble compounds that enhanced the solubility of anthracene in aqueous solution. Soil components did not have a significant effect on growth or degradation. Degradation of anthracene ceased when the concentration in soil dropped to approx. 30 g/g, from an initial value of 600 g/g. Correspondence to: M. R. Gray     

In vitro comparison of ceftazidime,aztreonam, cefpirome,gentamicin, imipenem,enoxacin, and ticarcillin plus clavulanic acid against 108 strains ofPseudomonas maltophilia

Pseudomonas maltophilia is an uncommon cause of hospital-acquired infection and is resistant to most of the antimicrobial agents used in the treatment of gram-negative infections. Susceptibility of 108 isolates ofP. maltophilia to ceftazidime, aztreonam, defpirome, gentamicin, imipenem, enoxacin, and ticarcillin plus clavulanic acid was determined by an agar dilution method. The isolates were in general resistant to the antibiotics. Imipenem and cefpirome were not active at clinically achievable levels. Of the isolates, 20% were susceptible to 16 g/ml ceftazidime, 53% were susceptible to 4 g/ml enoxacin, 10% were susceptible to 4 g/ml gentamicin, and 25% were susceptible to 64 g/ml ticarcillin plus 2 g/ml clavulanic acid.     

Butachlor influence on selected metabolic processes of plant cells and tissues

Time- and concentration-course studies were conducted to determine the effects of butachlor (N-[butoxymethyl]-2-chloro-2,6-diethylacetanilide) on photosynthesis, protein synthesis, RNA synthesis, and lipid synthesis using isolated leaf cells of red kidney bean (Phaseolus vulgaris L.). At the 2-h incubation period, butachlor inhibited photosynthesis, protein synthesis, RNA synthesis, and lipid synthesis 99, 99, 96, and 81% respectively at 100 M, and 0, 19, 17, and 40% respectively at 10 M. At 100 M and 15-, 30-, and 60-min incubations, RNA synthesis was inhibited 20, 76 and 90% respectively, and lipid synthesis 35, 48, and 62% respectively; photosynthesis and protein synthesis were inhibited over 90% at all of these time periods. The effects of 50 M butachlor on protein and RNA synthesis in rice (Oryza sativa L.) and barnyardgrass (Echinochloa crusgalli L.) root and shoot segments were also investigated. Protein synthesis was inhibited in both species and to a greater degree in roots (81–90%) than in shoots (55–65%). RNA synthesis was inhibited 33% in barn-yardgrass roots but not significantly in barnyardgrass shoots or either organ of rice.     

Effects of paraquat on selected microbial activities in soil

Paraquat, applied as Gramoxone, to a nonamended sandy loam soil at five times the suggested field application rate (10 lb/A 115g/cm²) increased the numbers of bacteria, actinomycetes, and fungi during a 14-day incubation at 25°C. This increase was attributed to the use of compounds in the Gramoxone formulation rather than the use of paraquat. Treatment at one and five times the normal rate reduced CO₂ evolution by 44% and 67%, respectively, in soil amended with 2% glucose during a 12-day incubation. Similar treatments reduced CO₂ evolution in 1% straw-amended soil by 39% and 58%, respectively, during a 28-day incubation. Cellulose decomposition of cotton duck containing 13 and 176g of paraquat per milligram of material was inhibited for 15 and 28 days, respectively, in soil containing a large population of cellulolytic microorganisms. A concentration of 5000g/gm of paraquat was necessary to inhibit nitrification in soil by 44% druing a 28-day incubation at 20°C. Paraquat inhibited C₂H₂ reduction in artificial aggregates of soil amended with 2% glucose and incubated anaerobically at 25°C. Nitrogenase activity in aggregates was inhibited by 43% and 52% at concentrations of 580 and 720g/gm of paraquat respectively. The inhibitory effects of the herbicide were reduced when soil was amended with organic matter in the form of peat or straw. The availability of paraquat controlled the toxicity of the herbicide to soil microorganisms.     

Plasmid incidence in bacteria from agricultural and industrial soils

Heavy metal contents of agricultural and industrial soils were determined by atomic absorption spectrophotometry. The analysis of the samples collected from two different locations revealed significantly high levels of Fe, Zn, Cu, Cr and Ni. Certain microbiological parameters (total aerobic heterotrophs, asymbiotic N₂-fixers, total Actinomycetes and fungi) were also monitored from these soils. A total of 70 bacterial isolates from agricultural and industrial soils were examined for plasmid DNA content and resistance to the antibiotics amoxycillin, cloxacillin, chloramphenicol, doxycycline methicillin, nalidixic acid, and tetracycline. Minimum inhibitory concentrations (MICs) of Cu, Cr, Pb, Cd, Hg, Zn, and Ni for each isolate were also determined. Resistance was most frequent to methicillin (48.5%), cloxacillin (45.7%), and nalidixic acid (40%) for all isolates of bacteria. The highest MICs observed were 100 g/ml for mercury, 800 g/ml for Ni and 1600 g/ml for other metals. The incidences of metal resistance and MICs of metals for bacteria from industrial soil were significantly different to those of agricultural soil. On a percentage basis, 91.4% of the total bacterial isolates from industrial soil were found to harbour plasmids whereas 40% of the isolates from agricultural soil contained plasmids.     

Accelerated degradation of <Emphasis Type="Italic">N,N′</Emphasis> (DBU) upon repeated application

In a recent study on the degradation of N,N-dibutylurea (DBU), a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate^® fungicides, degradation half-lives of 1.4–46.5days were observed across several soils incubated at various combinations of soil moisture potential (–0.03 and –0.1MPa) and temperature (23, 33, and 44°C) for a single DBU application of 0.08 and 0.8 g g^–1 (Lee et al. 2004). However, Benlate^® can be applied as often as every 7days resulting in the repeated application of DBU likely to be present in the Benlate^® over a growing season. In this study, the effect of seven repeated DBU applications on mineralization rate was investigated in two soils, which encompass the range in rates previously observed. For the slower degrading soil, repeated DBU application increased mineralization from 0.029 to 0.99day^–1 at the 0.08 g g^–1 rate, and 0.037 to 0.89day^–1 at the 0.8 g g^–1 rate. For the faster degrading soil, effects on mineralization of repeated DBU applications were small to negligible. For the latter soil, the effect on mineralization of applied DBU concentrations from 0.0008 to 80 g g^–1 was also investigated. Mineralization rates decreased from 0.43 to 0.019day^–1 with increasing DBU concentrations. However, the amount of DBU mineralized by day 70 was similar across concentrations and averaged 83% of applied. Microbial respiration was not affected by increasing DBU concentrations. These findings support the supposition that DBU is readily degraded by soil microorganisms, thus unlikely to accumulate in agricultural soils.     

Developmental aspects of long-term callus culture ofVicia faba L.

Summary Vicia faba callus line (VFS 1), isolated from expiants of immature embryo, grew satisfactorily onMurashige andSkoog complete medium with 1.38 M 2,4-D, or with 0.92 M 2,4-D to which 1.0 M kinetin was added. It also grew well on the B 5 modified medium containing 2.3 M 2,4-D and 25.0 M kinetin. On the last of these media the cultures grew more uniformly and without necrosis. They also showed diminishing variation in polyploidy in favour of diploids and corresponding aneuploids (hypodiploids).After being cultured for nearly three years on MS containing 1.38 M 2,4-D, 8–33% of cultures of VFS 1 were able to regenerate roots when transferred to either MS half strength with 5.37 M NAA, or to a medium without 2,4-D, or else to media with the addition of kinetin only (in various concentrations).     

Clearance rates of bacteria-sized particles by freshwater ciliates,measured with monodisperse fluorescent latex beads

Summary Monodisperse fluorescent latex particles with diameters of 0.57 and 1.04 m have been used to measure the clearance rates of bacteria-sized particles by two ciliates from a Norwegian lake. The clearance rates by Epistylis rotans on these particles were in the range 0.23 to 1.26 l ind^-1h^-1, and by Strombidium sp. 0.26 to 0.90 l ind^-1 h^-1. The clearance rates varied with food level and temperature. Possibilities and limitations of the suggested method are discussed.     

Phosphorus and nitrogen status in soils and vegetation along a toposequence of dystrophic rainforests on the upper Rio Negro

Amazon forests along a toposequence at San Carlos de Rio Negro (Venezuela) show distinct nutrient limitations depending on slope position. Soils were collected by genetic horizons and analysed to provide information on the relationships between soil P and N status and the nutrition of natural forest at three locations along the toposequence. The upper-slope tierra firme sites had total P concentrations between 100 and 200 g g^–1 in the mineral soil fines and between 700 and 1100 g g^–1 in lateritic nodules. Hyphae were seen to explore lateritic nodules and may contribute to P nutrition. Total P in the mineral soil of the lower slope ranged from only 3 to 130 g g^–1. In both the organic mats of the tierra firme and the humic horizon at the lower-slope tall Amazon caatinga site, 50–60% of the P was in inorganic forms, which, in the absence of P-fixing mineral soil, maintain high levels of plant-available P. As a result, the litter mats and humic horizon accounted for over 70% of the total available P in these soils. The proportion of available P increased, and P sorption decreased, downslope, supporting ecological studies which found that tall Amazon caatinga was least P-limited. Soil N and C levels show a maximum at the mid-slope and a minimum at the lower slope. Distributions of biomass C, N and P closely follow those of soil C, N and available (but not total) P along the slope.     

Diurnal changes in proline content of desert plants

Summary The diurnal changes in proline and water contents of Zygophyllum quatarense and Francoeuria crispa were investigated under desert conditions. In both plants, the proline content was low before sunrise amounting to 10.42 moles/g fresh weight in Zygophyllum and 6.3 moles/g fresh weight in Francoeuria. By the progress of the day and the intensification of the evaporative power of the atmosphere, the proline content increased considerably in the two plants. The proline content reached maximal values at 5 p.m., reaching 23.36 moles/g in Zygophyllum and 11.16 moles/g in Francoeuria. The proline content of the artificially watered plants was kept at a low level throughout the day. The conditions and role of proline accumulation were discussed.     

Transformation of Atriplex gmelini plants from callus lines using Agrobacterium tumefaciens

Atriplex gmelini plants were regenerated via organogensis from hypocotyl explants. Callus lines were induced from the hypocotyl explants on Linsmaier and Skoog (LS) medium supplemented with 1 M benzyladenine and 5 M -naphthaleneacetic acid in the dark. Shoots were regenerated from the callus lines on LS medium supplemented with 20 M thidiazuron and 0.1 M -naphthaleneacetic acid under a high-intensity light condition (450 mol m^–2 s^–1). The regenerated shoots were rooted on LS medium without growth regulators to obtain fully developed plants. We succeeded in transforming Atriplex gmelini from callus lines using Agrobacterium tumefaciens.     

Studies on Haematococcus pluvialis for improved production of astaxanthin by mutagenesis

Cultures of Haematococcus pluvialis were exposed to mutagens like u.v. and EMS (ethyl methanesulphonate). The results showed that the survival rate decreased with the increase in u.v. exposure time and increase in EMS concentration. These mutants were further screened using inhibitors of the carotenoid biosynthetic pathway viz. diphenylamine (15–90 M), nicotine (160–320 M) and compactin (1.5–3.0 M). The mutants thus obtained showed early enhanced (2.2–3.2-fold) astaxanthin accumulation and also exhibited higher lycopene cyclase activity.     

In vitro organogenesis of elephant apple (Feronia limonia)

Elephant apple (Feronia limonia L.). was micropropagated on MS medium containing 4.4 M benzyladenine and 4.6 M kinetin using cotyledon explants taken from in vitro-grown seedlings. Adventitious buds formed on the cotyledon developed into shoots that were rooted in half-strength MS medium containing 0.57 M indoleacetic acid and 0.49 M indolebutyric acid. Plants were successfully established in soil.Abbreviations BA 6-benzyladenine - IAA 3-indoleacetic acid - IBA 3-indolebutyric acid - MS Murashige & Skoog     

Identification of a cDNA encoding a plant Lewis-type alpha1,4-fucosyltransferase

Recently, it has been found that plants, including tomato (Lycopersicon esculentum), express the Lewis-a epitope, Gal1,3(Fuc1,4)GlcNAc, on some N-glycans. By searching the EST database, it was possible to identify a tomato cDNA encoding a protein, designated FucTC, of 413 amino acids with homology to plant and mammalian 1,3/4-fucosyltransferases. The cDNA was expressed in Pichia pastoris and the recombinant enzyme was found to transfer fucose from GDP-Fuc (K_m 16 M) to lacto-N-tetraose (Gal1,3GlcNAc1,3Gal1,4Glc; K_m 80 M) as well as to 1,3- and 1,4-galactosylated N-glycans. It is concluded that FucTC is responsible for the biosynthesis of Lewis-a on N-glycans in tomato.     

Effect of thidiazuron on vegetative tissue-derived somatic embryogenesis and flowering of bamboo Bambusa edulis

Current research on somatic embryogenesis of bamboo uses reproductive tissue as explants. However, it was hard to obtain the explant. Shoots of a local accession (3–4 m high) were used for multiple shoot production. In order to obtain embryogenic callus, nodal and internodal tissues from in vitro plantlets were placed on Murashige and Skoog (MS) medium supplemented with 9.2 M kinetin (KN), 13.6 M 2,4-dichlorophenoxyacetic acid (2,4-D), 0.1% (v/v) coconut milk, and 6% (w/v) sucrose. We studied the effects of sucrose and thidiazuron (TDZ) on callus proliferation. Optimal additives to the MS medium for embryogenic callus proliferation were 0.046 M TDZ, 13.6 M 2,4-D and 3% (w/v) sucrose. TDZ also promoted the germination of bamboo somatic embryos. The germination rate of the somatic embryos exceeded 80% on MS-based medium supplemented with 0.455M TDZ. Naphthaleneacetic acid (NAA) reduced germination. Well-developed plantlets were successfully transferred to soil. There was no albino mutant in subsequent culture. In vitro regenerants and potted plants flowered, but no seeds were produced.     

Effects of a new pyrazolo [3, 4-d]pyrimidine on growth and morphology of Candida albicans

A new pyrazolo [3, 4-d]pyrimidine derivative was synthesized and its antifungal activity evaluated in vitro against mycelial and yeast cells of Candida albicans. The most striking ultrastructural changes following treatment with 10–30 g/ml (mycelia) and 25–75 g/ml (yeasts) consisted in the deterioration of the organelle membranes and in aberrant thickenings of the cell wall. The complete disorganization of the cytoplasmic structures seemed to be the final event.     

Chemical composition of soil solutions extracted from New Zealand beech forests and West German beech and spruce forests

Concentrations of ions were measured in soil solutions from beech (Nothofagus) forests in remote areas of New Zealand and in solutions from beech (Fagus sylvatica) and Norway spruce (Picea abies) forests in North-East Bavaria, West Germany, to compare the chemistry of soil solutions which are unaffected by acid deposition (New Zealand) with those that are affected (West Germany). In New Zealand, soil solution SO₄ ^2– concentrations ranged between <2 and 58 mol L^–1, and NO₃ ^– concentrations ranged between <1 and 3 mol L^–1. In West Germany, SO₄ ^2– concentrations ranged between 80 and 700 mol L^–1, and NO₃ ^– concentrations at three of six sites ranged between 39 and 3750 mol L^–1, but was not detected at the remaining three sites. At all sites in New Zealand, and at sites where the soil base status was moderately high in West Germany, pH levels increased, and total Al (Al_t) and inorganic monomeric Al (Al_i) levels decreased rapidly with increasing soil depth. In contrast, at sites on soils of low base status in West Germany, pH levels increased only slightly, and Al levels did not decline with increasing soil depth.Under a high-elevation Norway spruce stand showing severe Mg deficiency and dieback symptoms in West Germany, soil solution Mg²⁺ levels ranged between 20 and 60 mol L^–, and were only half those under a healthy stand. Al_t and Al_i levels were substantially higher the healthy stand than under the unhealthy stand, indicating that Al toxicity was not the main cause of spruce decline.     

Response of Rhizobium leguminosarum to nickel stress

Rhizobium leguminosarum strain P-5 biovar viciae was sensitive to Ni²⁺ (MIC, 75 M) and showed concentration-dependent Ni²⁺ uptake in a wide concentration range (50–500 M). Ni²⁺ uptake up to a certain threshold limit also increased thiol content (66 nmol mg^–1 protein), proline content (10.85 nmol mg^–1 protein) and urease specific activity (500 nmol min^–1 mg^–1 protein) maximum corresponding to 100 M Ni²⁺ as the external concentration or 151 nmol Ni²⁺ mg^–1 protein as the intracellular buildup. Proline synthesis was stimulated most even at much lower Ni²⁺ concentration (25 M). Higher intracellular Ni²⁺ load neither favoured thiol nor proline biosynthesis nor urease activity. Ni²⁺ requirement of urease was ascertained by using EDTA-grown cells and the addition of bicarbonate (NaHCO₃, 100 mM) to the crude extract. The induction of thiol or proline by Ni²⁺, therefore, reflects the possible strategies adopted by bacterial cells to overcome the environmental stress.     

Changes with age in the absorption spectrum of chlorophyll α in a diatom

Summary Absorption spectra of a young and an old culture of the diatom Pheodactylum tricornutum were measured in thin layers between two opal glass sheets. The spectra at 24° and at -196°C were replotted to give equal areas from 730–625 m to allow direct comparison. At 24°C the spectrum for the difference between the two cultures had a negative component of 18 m half width centered at 675 m and a positive region of W_0.5=26 m near 700 m.The spectra at -196°C may be somewhat distorted by clumping of the cells during freezing but nevertheless the 16 day culture clearly showed a smaller proportion of Ca 670 to Ca 680. This older culture has a shoulder due to a 707 m component. The difference curve at -196°C shows the decrease of an unsymmetrical band peaking at 669 m and an increase at 695 m in addition to the 707 m component. Due to the possibility of distortion, the presence of an actual component at 695 is doubtful in these particular cultures.The room temperature spectrum in the chloropyhll a region for the 5 day culture can be closely fitted by a single probability curve at 675 m having a half-width of 31 m. The sum of two components, with widths more reasonable for chlorophylls, also matched the data well enough. These two probability curves, of 22 m half width, centered on 669 and 683.2 m and had a height ratio, h₆₆₉/h₆₈₃ of 1.18. In the 16 day culture the ratio for these bands changed to 1.11 and there was extra absorption around 700 m.Dedicated to Professor C. B. van Niel on the occasion of his 70th birthday