Increased taxane accumulation in callus cultures of Taxus cuspidata and Taxus × media by some elicitors and precursors

In Taxus cuspidata callus, vanadyl sulfate (10 mg l^–1) induced a high (146 g g^–1 dry wt) production of 10-deacetylbaccatin III in comparison to 7 g g^–1 dry wt of the control. The content of paclitaxel in this species increased from 16 g g^–1 to 74 g g^–1 dry wt when 20 mg phenylalanine l^–1 was used. In T. media, p-aminobenzoic acid induced the highest content of 10-deacetylbaccatin III (481 g g^–1 dry wt) versus 181 g g^–1 in the control. Paclitaxel increased from 89 to 139 g g^–1 dry wt after adding chitosan (20 mg l^–1) to the cultures.     

In vitro rosmarinic acid accumulation in sweet basil (Ocimum basilicum L.)

Leaf-derived suspension cultures of sweet basil, Ocimum basilicum L. accumulated rosmarinic acid up to 10 mg g^–1 dry wt, a value up to 11 times higher than in callus cultures or in leaves of donor plants. Immobilized cells accumulated less than 15 g rosmarinic acid g^–1.     

The contribution of size-fractionated plankton to biomass and primary production of phytoplankton in saline–alkaline ponds

Primary productivity, biomass and chlorophyll-a of size fractionated phytoplankton (<0.22 m, <3 m, <8 m, <10 m, <40 m, <64 m, <112 m and <200 m) were estimated in 6 ponds and 5 experimental enclosures. The results showed that the planktonic algae less than 10 m are important in the biomass and production of phytoplankton in saline–alkaline ponds. The production of size fractionated phytoplankton corresponding to <112 m, <10 m and <3 m in saline–alkaline ponds were 10.5 ± 6.6 , 8.6 ± 5.4 and 0.33 ± 0.1 mgC l^–1 d^–1, respectively. Mean community respiration rate was 1.80 ± 0.73, 1.69 ± 0.90 and 1.38 ± 1.12 mgC l^–1 d^–1, respectively. The average production of phytoplankton corresponding to micro- (10–112 m), nano- (3–10 m) and pico- (<3 m) were 1.61, 8.30 and 0.33 mgC l^–1 d^–1, respectively. The ratio of those to the total phytoplankton production was 15%, 79% and 3%, respectively. The mean respiration rate of the different size groups was 0.11, 0.31 and 1.38 mgC l^–1 d^–1; the ratio of those to total respiration of phytoplankton was 6%, 17% and 77%, respectively. The production of size-fractionated phytoplankton corresponding to <200 m, <10 m and <3 m in enclosures was 2.19 ± 1.63, 2.08 ± 1.75 and 0.22 ± 0.08 mgC l^–1 d^-1, respectively. Mean community respiration rates were 1.25 ± 1.55, 1.17 ± 1.42 and 0.47 ± 0.32 mgC l^–1 d^–1, respectively. The average production of phytoplankton corresponding to micro- (10–200 m), nano- (3–10 m) and pico- (<3 m) plankton was 0.11, 1.86 and 0.22 mgC l^–1 d^–1, respectively. The ratio of those to the total production of phytoplankton was 5%, 85% and 10%, respectively. The mean respiration rate of different size groups were 0.08, 0.72 and 0.46 mgC l^–1 d^–1, the ratio of those to total respiration of phytoplankton was 6%, 57% and 37%, respectively. The concentrations of chlorophyll-a of the phytoplankton in the corresponding size of micro- (10–112 m), nano- (3–10 m) and pico- (<3 m) plankton in the experimental ponds were 19.3, 98.2 and 11. 9 g l^–1, respectively. The ratio of those to the total chlorophyll-a was 15%, 76% and 9%, respectively. The concentrations of chlorophyll-a of phytoplankton micro- (10–200 m), nano- (3–10 m) and pico- (<3 m) plankton in enclosures were 1.7, 34.3 and 3.0 g l^–1, respectively. The ratio of those to the total chlorophyll-a was 4%, 88% and 8%, respectively.     

Production of plumbagin from cell cultures of Plumbago rosea L.

Callus and suspension cultures derived from leaf explants of Plumbago rosea were established and plumbagin, a naphthoquinone, was isolated from them and confirmed by ¹H NMR and electron-ionization mass spectroscopy. Maximum content of plumbagin was obtained in the stationary phase of growth (4.3 mg g^–1 dry cell wt). Media pH, phytohormones and carbon sources were optimized for biomass and plumbagin accumulation. Cell aggregates, measuring 500 m in diam, produced 8.2 g dry cell wt l^–1, but larger aggregates (above 500 m) favored plumbagin accumulation with an yield of 4.5 mg g^–1 dry cell wt.     

Effect of 2-hydroxybenzoate on the rate of naphthalene mineralization in soil

The effect of 2-hydroxybenzoate (2-OHB, salicylate) on the mineralization rate of [¹⁴C]naphthalene, the population density of naphthalene-degrading bacteria, and the concentration of genes encoding for naphthalene dioxygenase in a soil bacterial community was investigated. Six different concentrations of 2-OHB (10, 20, 50, 100, 150 and 200 g g^–1 soil) were tested in 100-g portions of soil. The addition of 10, 20 or 50 g 2-OHB g^–1 soil produced a general increase in total soil bacterial population density, whereas the addition of 100 g or 200 g 2-OHB g^–1 soil specifically increased the proportion of naphthalene degraders relative to the total population. The addition of 50 g 2-OHB g^–1 soil produced a fourfold increase (the maximum observed) in the rate of naphthalene mineralization relative to the rate in unamended soil. The concentration of 2-OHB ( 100 g/g) added to soil correlated with the population density of naphthalene degraders (r=0.961). Addition of up to 200 g 2-OHB g^–1 correlated with the abundance of DNA sequences homologous to known naphthalene dioxygenase genes (nahAB) (r=0.958). However, mineralization of [¹⁴C]naphthalene was stimulated significantly only by the addition of 50 g 2-OHB g^–1 soil. Results of the mineralization experiments were supported by the detection of nahAB mRNA extracted directly from soil. The specificity of the effect of 2-OHB on naphthalene biodegradation was confirmed in a control experiment using equivalent concentrations of 4-OHB which repressed naphthalene mineralization by about 50%. Addition of ammonium nitrate to the soil also increased the rate of naphthalene mineralization. Ammonium nitrate added together with 2-OHB reduced the mineralization enhancement effect of either compound alone. The study confirmed that specific induction of biodegradative genes can enhance chemical pollutant removal in situ. Correspondence to: O. A. Ogunseitan     

Changes in phosphorus concentrations and pH in the rhizosphere of some agroforestry and crop species

The aim of this work was to assess whether agroforestry species have the ability to acquire P from pools unavailable to maize. Tithonia diversifolia(Hemsley) A. Gray, Tephrosia vogelii Hook f., Zea mays and Lupinus albusL. were grown in rhizopots and pH change and depletion of inorganic and organic P pools measured in the rhizosphere. Plants were harvested at the same growth stage, after 56 days for maize and white lupin and 70 days for tithonia and tephrosia, and the rhizosphere sampled. The rhizosphere was acidified by tithonia (pH change –0.3 units to pH 4.8) and lupins (–0.2 units to 4.9), alkalinised by tephrosia (+0.4 units to pH 5.4), and remained unchanged with maize growth. Concurrent with acidification in the rhizosphere of tithonia there was a decline in resin-P (0.8 g P g^–1). However, there was also a decline in NaOH extractable inorganic P (NaOH-P_i) (5.6 g P g^–1 at the root surface) and organic P pools (NaOH-P_o) (15.4 g P g^–1 at 1.5 mm from the root), which would not be expected without specific P acquisition mechanisms. Alkalinisation of tephrosia rhizosphere was accompanied by changes in all measured pools, although the large depletion of organic P (21.6 g P g^–1 at 5 mm from the root) suggests that mineralisation, as well as desorption of organic P, was stimulated. The size of changes of both pH and P pools varied with distance away from the rhizoplane. Decline of more recalcitrant P pools with the growth of the agroforestry species contrasted with the effect of maize growth, which was negligible on resin-P and NaOH-P_i, but led to an accumulation of P as NaOH-P_o (14.2 g P g^–1 at 5 mm from the root). Overall the depletion of recalcitrant P pools, particularly P_o, suggests that the growth of tithonia and tephrosia enhance desorption and dissolution of P, while also enhancing organic P mineralisation. Both species appear to have potential for agroforestry technologies designed to enhance the availability of P to crops, at least in the short term.     

Arsenic concentrations in water and fish from Chautauqua Lake,New York

Synopsis Arsenic persists in Chautauqua Lake, New York waters 13 years after cessation of herbicide (sodium arsenite) application and continues to cycle within the lake. Arsenic concentrations in lake water ranged from 22.4–114.81 g l^–1, = 49.0 ag l^–1. Well water samples generally contained less than 10 g l^–1 arsenic. Arsenic concentrations in lake water exceeded U.S. Public Health Service recommended maximum concentrations (10 g l^–1) and many samples exceeded the maximum permissible limit (50 g l^–1). Fish accumulated arsenic from water but did not magnify it. Fish to water arsenic ratios ranged from 0.4–41.6. Black crappie (Pomoxis nigromaculatus) contained the highest arsenic concentrations (0.14–2.04 g g^–1 ), X = 0.7 g g^–1) while perch (Perca flavescens), muskellunge (Esox masquinongy) and largemouth bass (Micropterus salmoides) contained the lowest concentrations (0.02–0.13 g g^–1). Arsenic concentrations in fish do not appear to pose a health hazard for human consumers.     

Growth and betacyanin production by hairy roots of Beta vulgaris in airlift bioreactors

Hairy roots of red beet (Beta vulgaris L.) were cultivated in different types of airlift bioreactors (cone, balloon, bulb, drum and column bioreactors of 5 l capacity and containing 3 l of half strength Murashige & Skoog medium). The cone type of airlift bioreactor gave the highest biomass of hairy roots and betacyanin accumulation. Betacyanin accumulation was 27 mg g^–1 dry wt in cultures aerated at 0.3 vvm. Light irradiation of 20 mol m^–2 s^–1 promoted hairy root growth but optimum betacyanin (34 mg g^–1 dry wt) accumulation was with the cultures grown under 60 mol m^–2 s^–1.     

The quantitative analysis of chromosome pairing and chiasma formation based on the relative frequencies of M I configurations

Whilst reliable estimates of chiasma frequencies can usually not be obtained, the probability (b) of a chromosome arm to be bound by at least one chiasma can often be determined. In the absence of interference this probability equals (1–e ^–2), where 2 is the average chiasma frequency of the chromosome arm and the average crossover frequency or map length. In the presence of interference is shown to retain its genetic meaning as an additive metric that may describe the chromosome arm or other distinctive chromosome segment in terms of genetic recombination. It is a form of potential map length, comparable to, but numerically different from the regular map length. It is termed provisionally crossing-over potential.A chromosome with armsm andn with crossing-over potentials and will form ring bivalents with a frequency (1–e ^–2).(1–e ^–2); open bivalents with a frequency (1–e ^–2).e ^–2+(1–e ^–2).e ^–2; univalent pairs with a frequencye ^–2.e ^–2. Estimates of these frequencies yield equations from which and may be solved. In rye (Secale cereale) their ratio (q) is approximately two and differs from the mitotic arm length ratio of 1.4, indicating localization of chiasmata in the long arms.Graphs are given to show how, with constantq, the relation between the probabilitiesb _m andb _n of the two arms being bound changes with changing averageb.Data are presented on chiasma frequencies in M I, and compared with the frequencies expected in the absence of interference to give an impression of the degree of interference. Apparent fusion of chiasmata simulates interference.     

Pesticides and heavy metals in Danish streambed sediment

The role of streambed sediment as a sink for pesticides and heavy metals was investigated in 30 Danish lowland streams. The investigated streams drain catchments varying in hydrology, topography, soil type and land use. The <250 m newly accumulated fraction of the uppermost 1–2 cm layer of streambed sediment was analysed for 19 old and modern pesticides and 9 heavy metals. DDE was present in the sediment of all the streams. Of the herbicides, fungicides and insecticides currently in use, the most frequently detected was diuron (50.0%), fenpropimorph (66.7%) and lambda-cyhalothrin (6.7%), respectively. The pesticides detected in the highest concentration were fenpropimorph (1700 ng g^–1), propiconazole (130 ng g^–1) and isoproturon (110 ng g^–1). The heavy metals are listed in order of increasing median concentration: Cd (0.80 g g^–1), Co (9.1 g g^–1), As (12.0 g g^–1), Ni (19.0 g g^–1), Cr (19.2 g g^–1), Pb (19.7 g g^–1), Cu (20.1 g g^–1), V (28.5 g g^–1), Zn (103 g g^–1). The average number of pesticides detected in the 27 streams draining predominantly agricultural catchments was (3.7±2.0) being higher (p=0.077) than in the three streams draining non-agricultural catchments (1.7±0.6). Pesticides were significantly related to catchment size, soil type and hydrological regime. Several heavy metals (Cr, Cu, Pb, V and Zn) were related to urban activity and soil type.     

Effect of the insecticides methylpyrimifos and chlorpyrifos on soil microflora in an agricultural loam

A study of the effects of two selected organophosphorus insecticides methylpyrimifos and chlorpyrifos on soil microflora in an agricultural loam was made. The insecticides had concentrations of 10 to 300 g g^–1. The presence of methylpyrimifos at concentrations of 100 to 300 g g^–1 or chlorpyrifos at concentrations from 10 to 300 g g^–1 significantly decreased aerobic dinitrogen fixing bacteria and dinitrogen fixation. Nitrifying bacteria decreased at concentrations of 200 and 300 g g^–1 of methylpyrimifos. The presence of 10 to 300 g g^–1 of chlorpyrifos decreased the total number of bacteria. However, fungal populations and denitrifying bacteria were not affected as a consequence of the addition of the organophosphorus insecticides to the agricultural soil, showing that these microorganisms can tolerate high amounts of those insecticides.     

Optimization of growth and fatty acid composition of a unicellular marine picoplankton,Nannochloropsis sp., with enriched carbon sources

A unicellular marine picoplankton, Nannochloropsis sp., was grown under CO₂-enriched photoautotrophic or/and acetate-added mixotrophic conditions. Photoautotrophic conditions with enriched CO₂ of 2800 l CO₂ l^–1 and aeration gave the highest biomass yield (634 mg dry wt l^–1), the highest total lipid content (9% of dry wt), total fatty acids (64 mg g^–1 dry wt), polyunsaturated fatty acids (35% total fatty acids) and eicosapentaenoic acid (EPA, 20:53) (16 mg g^–1 dry wt or 25% of total fatty acids). Mixotrophic cultures gave a greater protein content but less carbohydrates. Adding sodium acetate (2 mM) decreased the amounts of the total fatty acids and EPA. Elevation of CO₂ in photoautotrophic culture thus enhances growth and raises the production of EPA in Nannochloropsis sp.     

Influence of nitrogen on the behaviour of nickel in wheat

A glasshouse experiment was conducted to study the effect of Ni on the growth and nutrients concentration in wheat (Triticum aestivum Cv. WH 291) in the presence and absence of applied N as urea. Responses to N application were observed up to 120 g N g^–1 soil. No response to Ni was observed in the dry matter yield of wheat tops (leaves + stem) in the absence of applied N while in the presence of applied N, significant yield increases were obtained at 12.5g Ni g^–1 soil. Nickel was not toxic to wheat up to 50g Ni g^–1 soil in the presence of 120g N g^–1 soil. Nitrogen and Ni concentration in wheat tops and roots increased with increasing levels of applied N and Ni, respectively. Applied Ni had an antagonistic effect on N concentration. Similarly, N reduced the Ni concentration in the wheat tissues. Positive growth responses to Ni were associated with 22 and 15g Ni g^–1 in wheat tops, in the presence of applied N at 60 and 120g N g^–1 soil, while Ni toxicity was associated with 63, 92.5 and 112.5g Ni g^–1 in wheat tops, in the absence and presence of applied N at 60 and 120g N g^–1 soil, respectively.     

Indigo production in hairy root cultures of Polygonum tinctorium Lour.

The transformed root culture of Polygonum tinctorium Lour. was established by infecting leaf explants with Agrobacterium rhizogenes A4. These cultures were examined for their growth and indigo content under various culture conditions. Among the four different culture media tested, SH medium showed the highest yield for root growth (28 mg dry wt/30 ml) and indigo production (152 g/dry wt). In SH medium, 30 g sucrose l^–1, 2500 mg KNO₃ l^–1, 300 mg NH₄H₂PO₄ l^–1 were the best conditions for indigo production at pH 5.7. The production of indigo in hairy roots slightly increased with the addition of 200 mg chitosan l^–1 (186 g/dry wt) and 20 U pectinase l^–1 (181 g/dry wt).     

Changes in benthic community structure following construction of a harbour impoundment scheme

Long-term monitoring (May 1990 – November 1994) of benthic macrofauna and sediment composition was undertaken to examine changes in community structure following the construction of a tidal barrage at the entrance to Sutton Harbour, Plymouth (South West England). The harbour has permanently anoxic sediments, below a depth of 3 cm, consisting mainly of silt with relatively high total metal concentrations in the m<63 m fraction for Cu (96 – 222 g g^–1), Hg (0.7 – 2.0 g g^–1), Pb (93 – 297 g g^–1) and Zn (114 – 460 g g^–1). Polychaete worms, particularly of the family Cirratulidae, dominated the 93 taxa that form the macrofauna of the fine sediments. Multi-dimensional scaling (MDS) identified significant changes, surpassing all seasonal variability, in benthic community structure between pre-construction and construction phases and the similarities percentages procedure (SIMPER) isolated the species differentiating pre- and post-construction samples. Principal components analysis (PCA) revealed changes in heavy metal concentrations and sediment size distribution, primarily between surveys encompassing the start of construction. Rank correlations between the biotic and abiotic similarity matrices (BIOENV) were highest for sediment Pb and Zn concentrations, indicating that these variables offered a potential explanation of the changes in community structure. The results demonstrate the sensitivity of the benthic community to man-induced change and the need for ecological factors to be accounted for in harbour development at other locations.     

Interrelationships Between Nitrogen Supply and Photosynthetic Parameters in Vicia faba L.

We determined for Vicia faba L the influence of nitrogen uptake and accumulation on the values of photon saturated net photosynthetic rate (P _Nmax), quantum yield efficiency (), intercellular CO₂ concentration (C _i), and carboxylation efficiency (C _e). As leaf nitrogen content (N_L) increased, the converged onto a maximum asymptotic value of 0.0664±0.0049 mol(CO₂) mol(quantum)^–1. Also, as N_L increased the C _i value fell to an asymptotic minimum of 115.80±1.59 mol mol^–1, and C _e converged onto a maximum asymptotic value of 1.645±0.054 mol(CO₂) m^–2 s^–1 Pa^–1 and declined to zero at a N_L-intercept equal to 0.596±0.096 g(N) m^–2. fell to zero for an N_L-intercept of 0.660±0.052 g(N) m^–2. As N_L increased, the value of P _Nmax converged onto a maximum asymptotic value of 33.400±2.563 mol(CO₂) m^–2 s^–1. P _N fell to zero for an N_L-intercept of 0.710±0.035 g(N) m^–2. Under variable daily meteorological conditions the values for N_L, specific leaf area (_L), root mass fraction (R_f), P _Nmax, and remained constant for a given N supply. A monotonic decline in the steady-state value of R_f occurred with increasing N supply. _L increased with increasing N supply or with increasing N_L.     

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

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

Inhibition of somatic embryo maturation in Sitka spruce [Picea sitchensis (Bong.) Carr.] by butylated hydroxytoluene,a volatile antioxidant released by parafilm

Head-space volatiles above embryogenicPicea sitchensis (Bong.) Carr. (Sitka spruce) tissues cultured in glass Petri dishes sealed with Parafilm M or cling-film, were captured on Tenax adsorption traps and analysed by gas chromatography / mass spectrometry. Each sealing system released a single major compound into the head-space; butylated hydroxytoluene from Parafilm M and 2-ethyl-1-hexanol from cling-film. After two weeks sealed under Parafilm M butylated hydroxytoluene accumulated to 1.1 g g^–1 FW in tissues and subsequent somatic embryo maturation was prevented. When butylated hydroxytoluene was supplied via the head-space (100 g/250 ml flask) 0.5 g g^–1 FW accumulated in tissues after two weeks and no somatic embryo maturation occurred. Potentially phytotoxic metabolites of butylated hydroxytoluene included a substituted stilbenequinone, butylated hydroxytoluene quinone methide and butylated hydroxytoluene dimer.     

Diagnosis of zinc deficiency in seedlings of a tropical eucalypt (Eucalyptus urophylla S. T. Blake)

A glasshouse experiment was undertaken to establish the internal Zn requirement for shoot growth of Eucalyptus urophylla, a fast-growing commercial plantation species widely planted in tropical regions of the world. A Zn-deficient sand was supplemented with ten rates of Zn and seedlings were harvested after three months. In Zn-deficient plants the new growth was dwarfed with small, necrotic leaves and short internodes. Foliar Zn concentrations declined markedly with leaf age in both Zn-deficient and Zn-adequate plants. The critical Zn concentration for the diagnosis of Zn deficiency also fell with leaf age. Zinc concentrations in the youngest fully expanded leaf ranged from 8–11 g Zn g^–1 dry weight in plants with severe symptoms to 30–37 g Zn g^–1 dry weight in non-deficient plants. The critical Zn concentration for the diagnosis of Zn deficiency at 90% of maximum shoot growth in the same leaf was 21 g Zn g^–1 dry weight. This value is nearly twice that reported for several other species of eucalypts and may indicate a higher internal demand for Zn in tropical than in temperate eucalypts.     

Improved growth of the red yeast, Phaffia rhodozyma (Xanthophyllomyces dendrorhous), in the presence of tricarboxylic acid cycle intermediates

Catabolites related to tricarboxylic acid cycle affected growth and carotenogenesis in Phaffia rhodozyma. Glutamate, glutamine, aspartate, asparagine and proline at 75 mM of N increased biomass from 2 g l^–1 to 2.9–4.7 g l^–1 but decreased carotenoid from 420 g g^–1 yeast to 200–260 g g^–1 yeast in strain 67-385. However, simple nitrogen sources did not decrease carotenoid formation. Tricarboxylic acid intermediates repressed carotenogenesis to a less degree than the corresponding amino acids. Carotenoid hyper-producing mutants were impaired in nitrogen utilization. These results indicated that nitrogen assimilation and the concentrations of tricarboxylic acid cycle intermediates are involved in regulation of carotenoid biosynthesis.