Copper but not iron limitation increases astaxanthin production by Phaffia rhodozyma in a chemically defined medium

The influence of copper (0–32 M) and iron (0–108 M) on growth and astaxanthin production by Phaffia rhodozyma was studied. Copper below 3.2 M increased the astaxanthin content of the cells (from 220 to 287 g g^–1) but at the expense of a slightly decreased growth (from 11.3 to 10.2 mg ml^–1). In contrast, iron below 1 M decreased both the growth and astaxanthin content of the cells. Using copper limitation instead of toxic respiratory inhibitors to improve astaxanthin production has obvious advantages from the product quality, environmental and process operation points of view.     

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.     

Tissue culture ofKarwinskia humboldtiana—a plant producing toxins with antitumoural effects

Isolated embryos ofKarwinskia humboldtiana were cultured in vitro. The growth of embryos and development to plantlets on woody plant medium supplemented with indole-3-acetic acid 6.10^-2 mol l^–1, gibberellic acid (GA₃) 3.10^-2 mol l^–1, and 6-benzylaminopurine (BA) 2 mol l^–1 was obtained. Multiplication of shoots and rooting of excised shoots has been achieved. Callus formation on modified Murashige-Skoog medium supplemented with 1-naphthaleneacetic acid 10 mol l^–1, GA₃ 14 mol l^–1, and kinetin 5 mol l^–1 on hypocotyls, or on root cultures on medium supplemented with 2.4-dichlorophenoxyacetic acid 10 mol l^–1 and BA 10 mol l^–1 was induced.Abbreviations BA 6-benzylaminopurine - 2,4-d 2,4-dichlorophenoxyacetic acid - GA₃ gibberellic acid - IAA indole-3-acetic acid - NAA 1-naphthaleneacetic acid - TEM transmission electron microscopy     

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.     

The kinetics of the degradation of chloroform and benzene in anaerobic sediment from the River Rhine

In anaerobic methanogenic sediment microcosms¹⁴C labelled chloroform was degraded mainly to carbon dioxide. At a concentration of 4 g.l^–1 the mineralization followed first order kinetics with a half life of 12 days at 10°C and 2.6 days at 20°C. At a concentration of 400 g.l^–1 the mineralization rate increased with time and followed logarithmic kinetics with a _max of 0.02.d^–1 at 10°C. The logarithmic kinetics can be explained by growth of the bacteria on the higher concentration of chloroform with a generation time of 35 days. Shaking and oxygenation did not inhibit the mineralization of chloroform, probably because of bacterial consumption of the dissolved oxygen. ¹⁴C labelled benzene was mineralized only for a small percentage to¹⁴C labelled carbon dioxide while other, not acid extractable, degradation products were formed. Under anaerobic conditions after one day when 5% of the benzene was degraded to carbon dioxide, the mineralization ceased, while the disappearance of benzene proceeded. With air in the headspace of the incubation bottles 25% of the benzene was mineralized to carbon dioxide. The anaerobic degradation of benzene at a concentration of 100 .l^–1 showed similar kinetics as the degradation at 1 g.l^–1. Hence no adaptation of the microflora in the sediment occurred during the 63 days of the experiment at 100 g.l^–1.     

Ecotoxicity of lead to the zebra musselDreissena Polymorpha,Pallas

The effect of lead on the filtration rate of the zebra musselDreissena polymorpha was investigated, together with the accumulation of Pb in the soft tissues of the mussels. The NOEC-filtration was 116 g.l^–1 (0,56 mol.l^–1) and the EC₅₀-filtration was 370 g.l^–1 (1.79 mol.l^–1). The NOEC-accumulation was the concentration found in the control water (1.4g.l^–1). These experiments show that the EC₅₀-filtration for Pb is similar to that for Cd, higher than that for Cu and lower than that for Zn. The water quality criteria for lead allow 25 g Pb.l^–1 in surface water. This will not cause short-term effects. Long-term effects may, however, occur, since an accumulation of Pb as low as 16 g.l^–1 was recorded in this study.     

Influence of inorganic microelements on the production of camptothecin with suspension cultures of <Emphasis Type="Italic">Camptotheca acuminata</Emphasis>

The effects of eight microelements (I^–, BO₃ ^3–, MoO₄ ^2–, Co²⁺, Cu²⁺, Mn²⁺, Fe²⁺, Zn²⁺) on the biosynthesis of camptothecin and the growth of suspension cultures of Camptotheca acuminata were studied. The increase of I^– to 25 M l^–1, Cu²⁺ to 1 M l^–1, Co²⁺ to 2 M l^–1 and MoO₄ ^2– to 10 M l^–1 in Murashige and Skoog (MS) medium resulted in 1.66, 2.84, 2.53 and 2.04 times higher of camptothecin yield than that in standard MS medium respectively. Combined treatment of I^– (25 M l^–1), Cu²⁺ (1 M l^–1), Co²⁺ (2 M l^–1) and MoO₄ ^2– (10 M l^–1) lead to improve cell dry weight, camptothecin content, and camptothecin yield to 30.56 g l^–1, 0.0299%, and 9.15 mg l^–1, respectively, which were 20.2, 208.9 and 273.8% increment respectively when compared with those of control.     

Micropropagation and ecorestoration of Vanda spathulata,an exquisite orchid

Node explants collected from flowering plants of Vanda spathulata, an endemic and exquisite orchid of Peninsular India and Sri Lanka, were cultured in Mitra medium with combinations of 4.4–88.8 m 6-benzyl adenine (BA) and 0.0–114.2 m indole-3-acetic acid (IAA). Combinations of 44.4 m BA with 17.1 or 28.5 m IAA and 66.6 mM BA with 28.5 or 40.0 m IAA induced maximum formation of 12.6 and 12.1 shoots / node, respectively, in a 6-month period. Subcultured nodal explants produced maximum of 6.1 shoots at combinations of 22.2–44.4 m 21 BA and 5.7–28.5 m IAA. Rooting of shoots occurred in medium containing 75 g l^–1 banana pulp and 5.7 m IAA within 3–9 weeks. Plantlets of 2–5 cm length possessing two to five roots established easily in community pots at 80–90% rates without hardening. Community potted plants introduced into forest segments at Ponmudi and Palode in Southern Western Ghats of India established at a rate of 50–70%.     

Abiotic metal stress enhances diosgenin yield in Dioscorea bulbifera L. cultures

Lower concentrations of CuSO₄ (25–75 M) in the MS medium supplemented with 0.1 mg l^–1 IAA+5.0 mg l^–1 Kn+500 mg l^–1 CH+10 mg l^–1 Cyst hyd enhanced the growth of regenerants of Dioscorea bulbifera L. CuSO₄ (75 M) induced an appreciable diosgenin yield in the regenerants compared to those obtained on media without Cu. The presence of Cu thus seems to stimulate diosgenin production. The regenerants also differentiated bulbils on lower concentrations of Cu. At CuSO₄ (100 M), however, cultures showed poor growth as well as a low diosgenin yield. Increased proline and protein contents were recorded in cultures grown on Cu-enriched media.     

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.     

Effects of cadmium on foraging behaviour of lake charr, Salvelinus namaycush

Synopsis Foraging behaviour of lake charr, Salvelinus namaycush, exposed to 0.5 and 5.0 g l^–1 cadmium concentrations for 106–112 d, was examined in a flow-through stream channel using fathead minnows, Pimephales promelas, as prey. Five modes of foraging behaviour were observed and quantified (ending at fixate-orient; ending at approach and/or chase; ending at failed attack; ending at capture and loss; successful consumption). Each mode represented an increasingly progressive end-point from initial sighting of the prey to final consumption. Compared to controls., 0.5 g l^–1 Cd-exposed predators captured significantly fewer prey, while 5 g l^–1 Cd-exposed predators made fewer attacks. Both Cd-exposed groups consumed fewer prey than controls.     

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.     

Concentrations of heavy metals and related trace elements in some Ethiopian rift-valley lakes and their in-flows

Concentrations of heavy metals commonly known to impact the environment and other related trace elements were quantified in the water bodies of nine Ethiopian rift-valley lakes and six rivers (their inflows) as well as in effluents from two factories. In about half of the samples the concentrations of As was 10–700 g l^–1 and Se, ranged from 10 to 28 g l^–1, were much higher than the maximum permissible level (MPL) according to international standards for drinking water. Mercury (Hg) was detected in four lakes and one river with high values ranging from 2 to 165 g l^–1. Concentrations of Mo in three soda lakes were as high as 544–2590 g l^–1. Iron (Fe) was found in high concentrations (567–4969 g l^–1) in three lakes, which are known to be discolored from inorganic colloids. Levels of Cd, Pb, and Cr ranged between 5 and 9, 12 and 20 and 104 and 121 g l^–1, respectively. The rest of the heavy metals analyzed, Ba, Cu, Mn, Ni and Zn, were either not detected in the samples or were found in much lower concentrations than the MPL for drinking water. Effluent from a tannery contained about 15, 141, 523, and 19 g l^–1 of As, Cr, Fe, and Se, respectively, and effluent from a textile factory contained high concentrations of As (10.6), Hg (3.8) and Se (20) g l^–1. Compared to more industrialized regions and other African lakes the concentrations of heavy metals in Ethiopian rift-valley lakes (with the exception of the soda lakes) and their inflows were low.     

Somatic embryogenesis of safflower: influence of auxin and ontogeny of somatic embryos

Influence of auxin type and concentration on somatic embryogenesis from cotyledonary explants of safflower was investigated. Embryogenic frequency as well as number of somatic embryos was dependent on auxin type and concentration. NAA at 10.74 M (2 mg l^–1) was optimum for high frequency of somatic embryos, whereas IAA provided the maximum number of somatic embryos per responding culture. Somatic embryo development was asynchronous and strongly affected by auxin type and concentration. Maximum numbers of well developed somatic embryos at the cotyledonary stage were obtained with 5.37 M (1 mg l^–1 ) NAA + 2.22 M (0.5 mgl ^–1) BA. Histological studies confirmed the unicellular origin of somatic embryos from the adaxial epidermis of the cotyledon. Broad base attachment of somatic embryos to the epidermis indicated the absence of a suspensor.     

Mixed-acid fermentation and polysaccharide production by Lactobacillus helveticus in milk cultures

Lactobacillus helveticus grown in milk with pH control at 6.2 had a slower growth rate (=0.27 h^–1) and produced less exopolysaccharide (49 mg l^–1) but increased lactic acid production (425 mM) compared to cultures without pH control (=0.5 h^–1, 380 mg exopolysaccharide l^–1, and 210 mM lactate), respectively. Both cultures displayed a mixed-acid fermentation with formation of acetate, which is linked not only to citrate metabolism, but also to alternative pathways from pyruvate.     

Isolation and identification of plant growth inhibitors as candidate(s) for allelopathic substance(s), from aqueous leachate from mesquite (Prosopis juliflora (Sw.) DC.) leaves

As candidate(s) for allelopathic substance(s), two plant growthinhibitors were isolated from aqueous leachate of leaves of mesquite, whichshowa strong allelopathy, and which were identified as syringin and(–)-lariciresinol by their spectral analyses. Syringin inhibited root andshoot growth of lettuce seedlings at concentrations greater than 0.8M, and root and shoot growth of barnyard grass seedlings atconcentrations greater than 2.7 and 26.9 M, respectively. Onthe other hand, (–)-lariciresinol inhibited root and shoot growth oflettuce seedlings at concentrations greater than 2.8 and 0.8M,and root and shoot growth of barnyard grass seedling at concentrations greaterthan 0.8 and 2.8 M, respectively. The contents of syringin and(–)-lariciresinol in the rhizosphere soil of mesquite were 0.34 and 0.38g/g soil, respectively. These results indicate that syringinand (–)-lariciresinol are allelopathic substance(s), and may play rolesinthe allelopathy of mesquite.     

Diurnal variation in physical-chemical properties and primary production in the interconnected marine,mangrove and freshwater biotopes of Kakinada coast,Andhra Pradesh,India

Diurnal variation in hydrological variables and dissolved inorganic nutrients such as PO _inf4 ^sup3– -P, N O _inf2 ^sup– -N, NO _inf3 ^sup– -N and NH _inf4 ^sup+ -N were studied in three interconnected biotopes including freshwater, marine and mangrove brackish water of the Kakinada coastal zone, Andhra Pradesh. Samples were collected at intervals of 3 hours, for a period of 24 hours. In the marine environment salinity varied from 26 to 32 whereas in the mangrove waters it fluctuated from 12 to 20 and in both biotopes salinity showed bimodal type of oscillation. Dissolved oxygen content was high in the mangrove waters during day time but decreased rapidly during the night hours. In the marine environment PO_f4 ^p3–-P concentration varied from 0.345 to 1.195 g at l^–1, NO _inf3 ^sup– -N from 1.03 to 6.62 g at l^–1 and NO _inf2 ^sup– -N from 0.086 to 0.506 g at l^–1. The highest and the lowest concentrations of PO _inf4 ^sup3– -P, NO _inf3 ^sup– -N, NO _inf2 ^sup– -N recorded in the mangrove waters were 0.790 and 0.325 g at l^–1, 7.10 and 1.60 g at l^–1 and 0.278 and 0.060 g at l^–1, respectively. The concentration of PO _inf4 ^sup3– -P, NO _inf3 ^sup– -N and NO _inf2 ^sup– -N were high in the freshwater canal, the maximum and minimum values being 1.110 and 0.730 g at l^–1, 26.40 and 9.98 g at l^–1 and 0.520 and 0.252 g at l^–1 respectively. The concentration of ammonia was relatively high in the mangrove water. Gross and net primary production in the mangrove water was 4 times higher than in the marine biotope. There was no export of dissolved nutrients from the mangrove environment to the adjacent marine waters.     

Somatic embryogenesis and plantlet regeneration from cell suspension cultures of palmarosa grass (Cymbopogon martinii)

A cell suspension culture was established from nodal callus ofCymbopogon martinii (Roxb.) Wats in a liquid medium containing Murashige and Skoog (1962) basal salts, vitamins, 100 mg 1^–1 myo-inositol and 20 g l^–1 of sucrose (MS) that was supplemented with 13.6 M 2,4-dichlorophenoxyacetic acid and 1.15 M kinetin. An initial inoculum density of 2 x 10⁴ cells ml^–1exhibited optimum cell growth. Calli were obtained 12–15 days after the suspension was plated onto semisolid medium of a similar composition. When calli were transferred to semisolid regeneration medium containing MS + 6.7 M N ⁶-benzyl-adenine + 1.15 M kinetin, somatic embryogenesis and plantlet regeneration occurred after 10–25 days. There was no significant decrease in the regeneration potential of the calli even when the cultures were initiated from 47-week-old cell suspensions. Chromosome counts of cells in suspensions, calli and somatic embryos derived from cultures of different ages revealed the presence of diploids, tetraploids and octaploids. However, the 33 regenerated plants tested were all diploid, indicating that only diploid cells were capable of regeneration in vitro.Abbreviations MS Murashige and Skoog (1962) basal salts with vitamins (100 mg1^–1 myo-inositol, 20 g1^–1 sucrose) - 2,4-D 2,4-dichlorophenoxyacetic acid - BA N ⁶-benzyl-adenine - Kn kinetin - MSC MS + 13.6 M 2,4-D + 1.15 M Kn - MSR MS +6.7 M BA + 1.15 M Kn     

Growth,photosynthesis and photorespiration of Lemna gibba: response to variations in CO2 and O2 concentrations and photon flux density

Dry weight and Relative Growth Rate of Lemna gibba were significantly increased by CO₂ enrichment up to 6000 l CO₂ l^–1. This high CO₂ optimum for growth is probably due to the presence of nonfunctional stomata. The response to high CO₂ was less or absent following four days growth in 2% O₂. The Leaf Area Ratio decreased in response to CO₂ enrichment as a result of an increase in dry weight per frond. Photosynthetic rate was increased by CO₂ enrichment up to 1500 l CO₂ l^–1 during measurement, showing only small increases with further CO₂ enrichment up to 5000 l CO₂ l^–1 at a photon flux density of 210 mol m^–2 s^–1 and small decreases at 2000 mol m^–1 s^–1. The actual rate of photosynthesis of those plants cultivated at high CO₂ levels, however, was less than the air grown plants. The response of photosynthesis to O₂ indicated that the enhancement of growth and photosynthesis by CO₂ enrichment was a result of decreased photorespiration. Plants cultivated in low O₂ produced abnormal morphological features and after a short time showed a reduction in growth.     

Inhibition of tumor growth in mice treated with synthetic muramyl dipeptide

Summary Treatment with synthetic MDP inhibited growth of transplantable, chemically induced tumors in syngeneic mice. The tumor-inhibitory effect was dependent on the schedule of MDP administration.Growth of SC transplants of a nonmetastasizing, MC-induced fibrosarcoma, MC11, was inhibited by local treatment with 200 g and 1,000 g MDP given SC 5–7 weeks before challenge. Treatment with lower (10 g and 100 g) doses of MDP and shorter (1–4 weeks) time intervals was not effective. Single doses of MDP (10–1,000 g) 1–3 weeks after challenge had no effect.Growth of IV-inoculated, metastasizing AAT-induced hepatoma A was inhibited by IV injections of 20 g MDP given 1 and 2 days prior to the challenge. Significant increases in the survival of hepatoma-bearing mice were observed only after injections of MDP incorporated in multilamellar liposomes.Abbreviations MDP n-acetylmuramyl-l-alanyl-d-isoglutamine - B10 C57BL/10ScSnPh mice - MC 3-methylcholanthrene - ATT o-amino-azotoluene - PBS phosphate-buffered saline