Interactions of carbaryl with estuarine bacterial communities

The addition of carbaryl (100g/ml) to a model estuarine ecosystem did not affect the number of bacteria in the sediment, but reduced the diversity (as measured by the rarefaction technique) of the microbial community as compared with a control model ecosystem. Two carbaryltolerant strains of bacteria were isolated from the carbaryl-treated system, but none were isolated from the control system. Bacterial growth and filter paper decomposition in mixed cultures was prevented by 100g/ml carbaryl, but this amount had no effect on the extracellular cellulase of an estuarine isolate. Increasing the amount of organic matter in the medium attenuated the toxicity of carbaryl to pure cultures of an estuarine isolate. The addition of 1, 10, or 100g/ml carbaryl to field plots had no effect on bacterial numbers, diversity, or filter paper decomposition. The amount of carbaryl in sediments exposed to 100g/ml fell below the limit of detection by thin-layer chromatography within 12 hours. In sterile and nonsterile model systems, carbaryl rapidly adsorbed to sediment, and hydrolyzed to 1-naphthol in both sediment and water. Although carbaryl may be toxic to bacteria under some conditions, the amounts that might enter and persist in an estuary are insufficient to have a significant impact on the sediment microbial community.     

Bacterial toxicity of cyclodextrins: Luminuous Escherichia coli as a model

The effect of various concentrations of natural and chemically modified cyclodextrins on the luminescence of an Escherichia coli suspension was investigated. All cyclodextrins were found to reduce, albeit to a varying degree, the luminescence level of the bacterial cells, thus suggesting a direct interaction between the cyclodextrins and cells. The inhibitory concentrations IC₂₀ and IC₅₀ of the various cyclodextrins were determined and taken to represent their toxicity effects upon the bacterial cells. Among the natural cyclodextrins, - and -CD interfered minimally with the bacterial luminescence and consequently were essentially non-toxic. The following descending order of toxicity was observed: -CD -CD > -CD. Among the chemically modified cyclodextrins, Dimeb was clearly toxic while Trimeb and the hydroxylated derivatives (hydroxypropyl-ga-CD, HPACD;--CD, HPBCD;--CD, HPGCD) were essentially non-toxic. The following descending order of toxicity was observed: Dimeb HPBCD > Trimeb > HPACD > HPGCD.     

Alleviation of aluminum toxicity to Rhizobium leguminosarum bv. viciae by the hydroxamate siderophore vicibactin

Acid rain solubilises aluminum which can exert toxic effects on soil bacteria. The root nodule bacterium Rhizobium leguminosarum biovar viciae synthesises the hydroxamate siderophore vicibactin in response to iron limitation. We report the effect of vicibactin on the toxicity of aluminum(III) to R. leguminosarum and kinetic studies on the reaction of vicibactin with Al(III) and Fe(III). Aluminum (added as the nitrate) completely inhibited bacterial growth at 25 M final concentration, whereas the preformed Al-vicibactin complex had no effect. When aluminum and vicibactin solutions were added separately to growing cultures, growth was partly inhibited at 25 M final concentration of each, but fully inhibited at 50 M final concentration of each. Growth was not inhibited at 50 M Al and 100 M vicibactin, probably reflecting the slow reaction between Al and vicibactin; this results in some aluminum remaining uncomplexed long enough to exert toxic effects on growth, partly at 25 M Al and vicibactin and fully at 50 M Al and vicibactin. At 100 M vicibactin and 50 M Al, Al was complexed more effectively and there was no toxic effect. It was anticipated that vicibactin might enhance the toxicity of Al by transporting it into the cell, but the Al-vicibactin complex was not toxic. Several explanations are possible: the Al-vicibactin complex is not taken up by the cell; the complex is taken up but Al is not released from vicibactin; Al is released in the cell but is precipitated immediately. However, vicibactin reduces the toxicity of Al by complexing it outside the cell.     

Sediment toxicity in the Kattegat and Skagerrak

Sediments were sampled from 62 sites in the Kattegat and Skagerrak, which are located between the Baltic and the North Sea in the Western Atlantic, during autumn 1989 and spring 1990. From each site 5 to 6 samples were taken wit ha box-corer. After mixing to composite samples on board, transport and storage (at 4 °C for 2 to 4 weeks), the samples were tested for toxicity to Daphnia magna and Nitocra spinipes. Immobility in Daphnia after exposure to 16 percent sediment (wet wt) in reconstituted standardized water (ISO, 1982) ranged from 0 to 88 percent after 24 h and from 3 to 95 percent after 48 h. For Nitocra the toxicity, determined as the 96-h LC50 (% wet wt) at 7 salinity, ranged from > > 32 percent (nontoxic) to 1.8 percent (most toxic). All exposures were made in duplicates and the effects obtained in the duplicates with the same sediment were correlated to each other. However, sediment toxicity to Daphnia and Nitocra was not. The test with Nitocra, which was made at several concentrations of sediment, was considered to give the most reliable picture of sediment toxicity in the Kattegat and Skagerrak. This ambient toxicity assessment identified three areas with toxic sediment, (1) the Göta älv estuary (outside the city of Göteborg) and its surroundings, (2) the Bay of Laholm in southern Kattegat, which is an area with periodic oxygen depletion and where repeated mussel kills have occurred during the last decade, and (3) an area in the open Skagerrak northwest of Skagen (the tip of the Jutland peninsula). Sediments, which had been stored at 4 °C, were tested again after 6 to 13 mos with the Nitocra test. Stored sediment toxicity was poorly correlated with fresh sediment toxicity. The average detoxification during storage was 5 times, but the range was 3 orders of magnitude, from 17 times more toxic to 73 times less toxic. The reasons for the observed areal and storage differences in sediment toxicity are so far not understood.     

Silicon amelioration of aluminium toxicity in teosinte (Zea mays L. ssp. mexicana)

The influence of different Al concentrations, (0, 60 and 120 M Al) on growth and internal concentrations of Al, Si and selected organic acids was analysed in plants of teosinte (Zea mays L. ssp. mexicana), a wild form of maize from acid soils from Mexico. The plants were grown in nutrient solutions (pH 4.0) with or without 4 M silicon. Analysis with the GEOCHEM speciation program did not reveal differences between free activities of Al³⁺ in solutions with and without 4 M Si, but solutions with Si yielded lower concentrations of monomeric Al species, [Al]_mono, when analysed by a modified aluminon method. Plants grown on solutions with similar [Al]_mono, but differing in silicon, showed highly significant differences in growth and tissue concentrations of Al and organic acids. Silicon prevented growth inhibition at [Al]_mono concentrations as high as 35 M, while plants grown without Si suffered severe growth reductions with 33 M [Al]_mono. In solutions with similar [Al]_mono concentrations plants with Si had lower tissue Al concentrations and higher concentrations of malic acid than plants without Si. In view of both the significant influence of Si on the response of plants to Al toxicity and the fact that some soluble Si is always present in soil solutions, the addition of low Si concentrations to nutrient solutions used for Al-tolerance screening is recommended.     

Seasonal succession,standing crop and determinants of primary productivity of the phytoplankton of Ministik Lake,Alberta, Canada

Ministik Lake (longitude 113°01; latitude 53°21), a well-mixed, shallow (mean depth 1.83 m), eutrophic lake is characterized by eutrophic chlorococcalean and cyanophycean phytoplankton associations, and little change in standing crop size with increasing depth. Standing crops and primary productivity are low during the winter but pronounced spring and late summer/early autumn maxima occur. Mean yearly areal standing crop (B) and primary productivity (A) were 199.2 mg m^–2 chlorophyll a and 319.5 mg C hr^–1 m^–2 respectively. Annual productivity was estimated at 1399,6 g C m^–2yr^–1. The mean increase in the extinction coefficient () per unit increase in standing crop (B) was 0.03 In units m^–1. High non-algal light attenuation (q) occurred averaging 46% which prevented the ratio B from attaining more than 74.2% of the theoretical maximum except once when selfshading occurred. Insignificant relationships existed between B (mg m^–3 chlorophyll a) and A_max (mg C hr^–1 m^–3), A and B and A and B. Close correlations existed between A and A_max/ and A and I₀ (W m^–2). The depth of the euphotic zone (Z_eu) varied between 0.6 and 2.0 m; the average relationship between z_eu and was z_eu = 3.78/_te, and the mean standing crop in the euphotic zone represented 58.3% of the theoritical maximum. The high _q values made the model of Talling (1957) inapplicable to this lake. The Q₁₀ value for the lake was 1.20. _max (mg C chlorophyll a ^–1 hr^–1) was closely related to both temperature and irradiance, and depressed by high pH values.Growth of the cyanophycean algae was correlated with temperature, chlorophycean algae with phosphate-phosphorus and temperature and the diatoms with dissolved silica and phosphate-phosphorus, but only in the case of Chaetoceros elmorii did any nutrient appear limiting. Indirect evidence that free CO₂ limited photosynthetic rates is provided by the _max:pH relationship.     

Early warning assays: an overview of toxicity testing with phytoplankton in the North American Great Lakes

The use of phytoplankton as test organisms in bioassays has recently gained momentum due to their simplicity, availability, sensitivity, rapidity of analysis, and cost-effectiveness. Increasing emphasis is currently being given to field and in situ experiments using indigenous populations, particularly ultraplankton/picoplankton (2–20 m) which play a key role in the microbial loop and food chain dynamics. Impact evaluation can be determined at the structural, ultra-structural, and functional level. An array of techniques is available for toxicity testing including the use of either algal cultures or natural assemblages in laboratory or in situ experiments, the selection of which depends on the objectives, precision required, and project budget of the particular study. An overview is presented of the various procedures using algae in toxicity testing with a focus on the Great Lakes and an emphasis on field techniques. The effective use and application of such sensitive technology has tremendous potential for early warning detection of ecosystem perturbations in concert with a multi-trophic battery of tests.     

Multiple Phosphorylation Sites and Quaternary Organization of Guanine-Nucleotide Exchange Complex of Elongation Factor-1 (EF-1βγδ/ValRS) Control the Various Functions of EF-1α

The eukaryotic guanine-nucleotide exchange factor commonly called elongation factor-1 (EF-1), comprises four different subunits including valyl-tRNA synthetase (EF-1/ValRS). The factor is multiply-phosphorylated by three different protein kinases, protein kinase C, casein kinase II and cyclin dependent kinase 1 (CDK1). EF-1/ValRS is organized as a macromolecular complex for which we propose a new structural model. Evidence that EF-1/ValRS is a sophisticated supramolecular complex containing many phosphorylation sites, makes it a potential regulator of any of the functions of its partner EF-1, not only involved in protein synthesis elongation, but also in many other cellular functions.     

Cell multiplication and ultrastructure ofMicrasterias denticulata (Desmidiaceae) grown under salt stress

Cells ofMicrasterias denticulata Bréb. were kept in nutrient solution of high osmolality (salt stress) for four weeks. In a special cell multiplication test it was established that cell division is gradually inhibited at increasing salt concentrations and totally arrested at the highest concentration (26 mosm/kg). Recovery studies proved that even cells from the highest concentration range start dividing immediately after being placed in aqua bidest. thus indicating the full reversibility of the inhibiting effect. — Cells of the highest concentration range show marked ultrastructural changes. Besides an enormous accumulation of starch and oil bodies and a condensed appearance of the ground plasma, a reduction of mitochondria, ER and the Golgi-system is found. The most striking effect occurs on the vacuolar system which appears extremely reduced and condensed. The cell wall is thickened by the formation of an additional cell wall layer with a spongy electron microscopical appearance. Through the cell wall many droplets of a probably fat-like substance are excreted. — In summary, salt stress induces growth-inhibited akinete cells in the sense ofFritsch; these can be reactivated by decreasing the salt concentration. The salt-induced akinete state seems to be an ecological adaption to unfavourable conditions rather than a degeneration of the cells.Dedicated to Prof. DrLothar Geitler on the occasion of his 90th birthday.23. 12. 1988     

Gramicidin toxicity in NG108-15 cells: protective effects of acetamidine and guanidine

Studies were conducted using a novel in vitro approach to investigate the efficacy of acetamidine hydrochloride (ACE) and guanidine hydrochloride (GUAN), previously shown to block gramicidin D (GRAM) channels in artificial membranes, in preventing the toxic effects of GRAM in NG108-15 (neuroblastoma×glioma hybrid) cells. Specifically, intracellular microelectrode techniques were employed to examine changes in membrane resting potential (V _m) and input resistance (R _in). At 1 mol/L, ACE significantly reduced loss of V _m induced by 1 or 10 g/ml GRAM, although higher concentrations of ACE did not afford enhanced antagonism. GUAN, in contrast, produced a concentration-dependent antagonism of GRAM-induced V _m and R _in loss, with high concentrations (10 or 100 mol/L) completely preventing diminutions in both V _m and R _in. In control cells superfused without GRAM, ACE produced a direct, concentration-dependent reduction in V _m and R _in, whereas GUAN hyperpolarized NG108-15 cells but did not alter R _in. These data represent the initial demonstration of the reversal of GRAM toxicity in an intact cell system.     

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.     

Energetic basis of cadmium toxicity in Staphylococcus aureus

In washed cells of cadmium-sensitive Staphylococcus aureus 17810S oxidizing glutamate, initial Cd²⁺⁺⁺ influx via the Mn²⁺ porter down membrane potential () was fast due to involvement of energy generated by two proton pumps—the respiratory chain and the ATP synthetase complex working in the hydrolytic direction. Such an unusual energy drain for rapid initial Cd²⁺ influx is suggested to be due to a series of toxic events elicited by Cd²⁺ accumulation down generated via the redox proton pump: (i) strong inhibition of glutamate oxidation accompanied by a decrease of electrochemical proton gradient ( _H ⁺) formation via the respiratory chain, (ii) automatic reversal of ATP synthetase from biosynthetic to hydrolytic mode, which was monitored by a decrease of _H ⁺-dependent ATP synthesis, (iii) acceleration of the initial Cd²⁺ influx down generated the reversed ATP synthetase, the alternative proton pump hydrolyzing endogenous ATP. The primary, cadmium-sensitive targets in strain 17810S seem to be dithiols located in the cytoplasmic glutamate oxidizing system, prior to the membrane-embedded NADH oxidation system. Inhibition by Cd²⁺ of _H ⁺-dependent ATP synthesis and of pH gradient (pH)-linked [¹⁴C]glutamate transport is a secondary effect due to cadmium-mediated inhibition of _H ⁺ generation at the cytoplasmic level. In washed cells of cadmium-resistant S. aureus 17810R oxidizing glutamate, Cd²⁺ accumulation was prevented due to activity of the plasmid-coded Cd²⁺ efflux system. Consequently, _H ⁺-producing and -requiring processes were not affected by Cd²⁺.     

Distribution and toxicity of a new colonial Microcystis aeruginosa bloom in the San Francisco Bay Estuary,California

The first distribution, biomass and toxicity study of a newly established bloom of the colonial cyanobacteria Microcystis aeruginosa was conducted on October 15, 2003 in the upper San Francisco Bay Estuary. Microcystis aeruginosa was widely distributed throughout 180 km of waterways in the upper San Francisco Bay Estuary from freshwater to brackish water environments and contained hepatotoxic microcystins at all stations. Other cyanobacteria toxins were absent or only present in trace amounts. The composition of the microcystins among stations was similar and dominated by demethyl microcystin-LR followed by microcystin-LR. In situ toxicity computed for the >75 m cell diameter size fraction was well below the 1 g l^–1 advisory level set by the World Health Organization for water quality, but the toxicity of the full population is unknown. The toxicity may have been greater earlier in the year when biomass was visibly higher. Toxicity was highest at low water temperature, water transparency and salinity. Microcystins from the bloom entered the food web and were present in both total zooplankton and clam tissue. Initial laboratory feeding tests suggested the cyanobacteria was not consumed by the adult copepod Eurytemora affinis, an important fishery food source in the estuary.     

Role of EDTA in a simple method for determining toxicity using a bacterial indicator organism

A method to determine toxicity using a bacterium as the indicator organism previously developed (Botsford 1998) perceives most divalent cations as being toxic. Mercury is perceived as the most toxic, followed by cadmium, zinc and copper. It was found that adding 2.5 m EDTA to the reaction would relieve the toxicity of the 15 divalent cations tested. This effect does not appear to be simple chelation. One micromolar EDTA eliminated the toxicity of 1.6 m calcium or 0.006 m mercury. Thirty-six chemicals were tested for their toxicity in the presence and absence of 2.5 m EDTA and 25 ppm calcium. Twenty-one were less toxic and two of these, p-aminobenzoic acid and tetrachloroethylene would no longer appear to be toxic according to the assay when these additions were present. Six chemicals had the same toxicity with and without the additions. Nine chemicals were more toxic when the EDTA and calcium were present. This experiment was repeated with six chemicals and ten times the EDTA concentration and ten times the calcium concentration. The toxicity with 10× was compared with the toxicity with 1× the additions. The toxicity of 4 of the six chemicals changed with the higher concentration of EDTA and calcium when the absorbancy values observed in samples with the lower levels were compared with samples with the higher levels. Obviously before EDTA can be added to mitigate the toxicity of divalent cations, it must be determined how much EDTA is required to eliminate the toxicity by the ions present in the sample. Alternatively, if the nature of the contaminating organic chemical is known, it can be determined what the effect of EDTA and the divalent cation present is on the apparent toxicity of the compound.     

Evaluating the contribution of magnesium deficiency in the aluminium toxicity syndrome in twelve sorghum genotypes

The contribution of Mg deficiency to Al stress in twelve different sorghum (Sorghum bicolor (L.) Moench) genotypes was investigated in nutrient solution culture under conditions of low Mg supply (between 50 and 1000 M) at two pH values. At pH 4.2, 30 M Al strongly inhibited Mg uptake. When dry matter yield was plotted as a function of the plant Mg concentration, similar response curves were obtained in the absence and the presence of Al with three genotypes. With many other genotypes dry matter yields of the control (without Al treatment) and Al-stressed plants were remarkably different at similar internal Mg concentrations, suggesting that growth had been suppressed not by Mg deficiency but by another factor, i.e. Al-induced root damage. At pH 4.8, 30 M Al hardly induced root damage but reduced Mg uptake and Al-induced Mg deficiency could almost completely account for the growth reaction of all genotypes. Therefore, at this pH the efficiency of uptake or use of Mg in different genotypes was the basis of their respective susceptibility to Al toxicity. When specific root length surpassed a certain critical range below 80–100 m per g dry root, growth control by Al-induced Mg deficiency was nearly abolished. The pH and Al concentration where this range was reached depended on the Al sensitivity of the genotypes.     

1H and13C-NMR analysis of four pentasaccharides from urine of blood-group A and B,Leb adults. Confirmation of the structure of two new oligosaccharides: Fuc(α1–2)[GalNAc(α1–3)]Gal(β1–3)[Fuc(α1–4)]Glc and Fuc(α1–2)[Gal(α1–3)]Gal(β1–3)[Fuc(α1–4)]Glc

The major pentasaccharides Fuc(1-2)[GalNAc(1-3)]Gal(1-4)[Fuc(1-3)]Glc and Fuc(1-2) [Gal(1-3)]Gal(1-4)[Fuc(1-3)]Glc, which are normally present in the urine of bloodgroup A Le^b and B Le^b healthy subjects, were each found to be contaminated by a minor component when analysed by¹H-NMR. The determination of these structures, Fuc(1-2) [GalNAc(1-3)]Gal(1-3)[Fuc(1-4)]Glc and Fuc(1-2) [Gal(1-3)]Gal(1-3)[Fuc(1-4)]Glc, was based on the results of methylation analysis and¹H/¹³C-NMR spectroscopy.Abbreviations HPLC high performance liquid chromatography - GLC gas liquid chromatography - NMR nuclear magnetic resonance - COSY correlation spectroscopy - Gal d-galactopyranose - GalNAc 2-acetamido-2-deoxy-d-galactopyranose - Glc d-glucopyranose - Fuc l-fucopyranose - LNDFH I lacto-N-difucohexaose I (Le^b determinant     

Quantitative cytology of the egg and central cell of Plumbago zeylanica and its impact on cytoplasmic inheritance patterns

Summary The egg and central cells of Plumbago zeylanica have an average volume of 543,000 m³ and 2,560,000 m³ respectively, with surface areas of 38,600 m² and 154,000 m². The egg contains an average of 39,900 mitochondria and 730 plastids. The majority of the plastids are perinuclear (> 60%) with less than 40% in lateral areas or near the filiform apparatus. After fertilization, the number of maternal organelles exceeds paternal organelles by a ratio of 11,000 for mitochondria and 154 for plastids. The central cell contains an average of 178,700 mitochondria and 1,840 plastids. After fertilization, these organelles far exceed the number of sperm organelles transmitted, by a ratio of approx. 14,000 for plastids and 1820 for mitochondria. Biparental inheritance of plastids in the embryo is possible, but not favored; the only comparable data in Oenothera and Impatiens reveals that biparental inheritance is possible in up to 124 ratios. Plants lacking biparental plastid inheritance do not contain plastids in the sperm, and thus the presence of even few sperm plastids may result in expression. The number of paternal mitochondria transmitted into the central cell is greater than that transmitted into the egg as the result of preferential fertilization with the mitochondrion-rich dimorphic sperm cell, although the ratio of paternal to maternal mitochondria is 11,000 in the egg and 1820 in the central cell. The similarity in these ratios suggests that there is a critical dosage of mitochondria that is permissible within the zygotic and endospermatic lineages. This may represent either: (1) a maximum permissible value to prevent expression of paternal mitochondrial genome, (2) a minimum ratio required in order to permit recombination of maternal and paternal mitochondrial genomes, or (3) a cytoplasmic genome balance number.Abbreviations mtDNA mitochondrial DNA - S_ua sperm cell unassociated with the vegetative nucleus - S_vn sperm cell physically associated with the vegetative nucleus     

Epigenetic Processes, when Natura Non Facit Saltum Becomes a Myth, and Alternative Ontogenies a Mechanism of Evolution

When I started the journal Environmental Biology of Fishes more than 25 years ago, it was designed to avoid any prejudices and scientific dogmas, to keep an open mind, and to allow publication of ideas that are irritating to followers of the so-called mainstream, ideas that few other journals dared to touch (Balon 1976, 1989d). While such articles in the journal were often ignored by the mainstream practitioners and the political establishment, none was ever opposed or proven wrong. As in many similar cases before, only time will show if these contributions were valid and of value to the advancement of knowledge.I have often wondered why it takes so long for some of the universal facts and ideas to be accepted or even to be known. I have come to believe that like with many textbooks some facts and conclusions are copied from one book to the next (as in the case of the origin of the common carp – Balon 1974, 1995a,b) without knowing or admitting that in the meantime new facts require new syntheses and conclusions. Even good scholars resist unknown facts or ideas. It is irritating that one's knowledge is inadequate or that others beat us to be first. I have wondered why wrong ideas persist for so long; but Bateson (1979, p. 206) already explained it to his daughter ... yes, your image of evolution is exact. And what Darwin called natural selection is the surfacing of the tautology or presupposition that what stays true longer does indeed stay true longer than what stays true not so long.After all it was Jean Baptiste Lamarckgrave, the founder of evolutionary theory, miserable, old, and blind, ... (Bateson 1972, p. xii) and/or Gottfried Treviranus who presented the truth long before the privileged Charles Darwin, alas in wrong languages. Over time, ignoring the truth became fashionable and the question which of the four theories of evolution (Løvtrup 1982) can be attributed to Darwin, if any, irrelevant. It is [exclaims Croizat 1977, transl. 1987, p. 137] a gross, very grave mistake to confuse Darwin as a historical figure with Darwin as an exalted figure of the thinking of biology (Croizat's italics).Nearly 30 years ago a BBC TV series and book on evolution glorified Darwin and molecular biology. Calder (1973, p. 9), the author of this book entitled The life game: evolution and the new biology felt that Darwin would [merely] need to know about the survival of the quickest, when it came to crossing the street. But the street was never crossed! Many TV viewers of the recent PBS series Evolution were again misled into believing that evolution was discovered by Darwin. Even Gould (2001) in the Introduction and the producer Hutton (2001) in the Foreword to the companion book of this series (Zimmer 2001) give the Darwinian evolution [sic] an exposé it hardly deserves. While such views have been repeatedly proven wrong, most scholars, with the exception of a few scientists, philosophers, and journalists, comfortably assume Darwin's priority in spite of numerous published evidences to the contrary. This myth is then fed to the general public. The following retrospective essay attempts to compile proofs in support of the evolutionary processes other than Darwin's natural selection and the gene-centric new synthesis, old by now as it is.     

New data on the toxic and radioprotective effect of cysteine onEscherichia coli 15 T- cells

Summary Exponential phase cultures ofE. coli 15 T^- cells growing on glucosemineral medium were supplemented with 2 mM l-cysteine-HCl. The optical density, acid soluble SH (AS-SH) as well as the DNA, RNA, and protein synthesis of the cultures were examined during this treatment and after return to normal growth conditions. Similarly, the survival of cells irradiated by a standard X-ray dose in cysteine-free buffer was measured.The development of radioresistance during the cysteine treatment as well as the loss of this acquired radioresistance after return to normal growth conditions could be divided into two phases: a) an instantaneous and b) a slow change of radioresistance. Phase a seems to be related to the changes occurring in the AS-SH content of the bacteria, while phase b is apparently dependent on the alterations in the synthesis of macromolecules.This work was partly presented at the 6th Annual Meeting of the European Society for Radiation Biology, Interlaken 1968.     

Sodium efflux from perfused giant algal cells

Internodal cells of the giant alga Chara corallina were perfused internally to replace the native cytoplasm, tonoplast and vacuole with artificial cytoplasm. Sodium efflux from perfused cells, measured by including ²²Na in the perfusion media, was increased by increasing the internal sodium concentration and by decreasing the external pH, and was inhibited by external application of the renal diuretic amiloride. The sodium efflux was markedly ATP-dependent, with a 50-fold decrease in efflux observed after perfusion with media lacking ATP. Efflux in the presence of ATP was reduced by 33% by inclusion of 10 M N,N-dicyclohexylcarbodiimide in the perfusion medium. The membrane potential of the perfused cells approximated that of intact cells from the same culture. It is suggested that sodium efflux in perfused Chara cells proceeds via a secondary antiporter with protons, regulated by ATP in a catalytic role and with the proton motive force acting as the energy source.Abbreviations DCCD N,N-dicyclohexylcarbodiimide - EGTA ethylene glycol-bis(-aminoethyl ether)-N,N,N,N-tetraacetic acid - Mes 2-(N-morpholino)ethanesulphonic acid - Mops 3(N-morpholino)propanesulphonic acid - Taps tris(hydroxymethyl)methylaminopropanesulphonic acid