Differential antimutagenic effects of caffeine and the protease inhibitor antipain on mutagenesis by various mutagens in Escherichia coli

The effects of caffeine (2 mg/ml) and the protease inhibitor antipain (1.75 mb/ml) in the plating agar medium on the yields of prototrophic revertants induced by 10 mutagens in E. coli uvrA^? strains were tested. Mutagenesis by 4-nitroquinoline 1-oxide was greatly diminished by both caffeine and antipain. UV mutagenesis was decreased moderately by caffeine, and greatly by antipain. X-Ray mutagenesis was decreased very slightly by both caffeine and antipain. Mutagenesis by N-hydroxyurethan was inhibited moderately by caffeine, and greatly by antipain; that by methyl methanesulfonate was inhibited moderately by both caffeine and antipain, and that by N-methyl-N′-nitro-N-nitrosoguanidine wa was not suppressed by caffeine but was inhibited moderately by antipain. Mutagenesis by ethyl methanesulfonate was inhibited greatly by caffeine, but only slightly by antipain. The antimutagenic effect of caffeine was strong on furylfuramide (AF-2) mutagenesis, moderate on that of mitomycin C (tested with B/r type strain) and negligible on that of N-methyl-N-nitrosourea. These diverse antimutagenesis patterns are briefly discussed in relation to the current idea that antipain antimutagenesis is due to inhibition of inducible error-prone repair.     

Effects of single and dual species herbivory on the behavioral responses of three thrips species to cotton seedlings

This study investigated the olfactory responses of 3 thrips species [Frankliniella schultzei Trybom, F. occidentalis Pergrande and Thrips tabaci Lindeman (Thysanoptera: Thripidae)] to cotton seedlings [Gossypium hirsutum L. (Malvales: Malvaceae)] simultaneously damaged by different combinations of herbivores. Cotton seedlings were damaged by foliar feeding Tetranychus urticae Koch (Trombidiforms: Tetranychidae), Helicoverpa armigera Hübner (Lepidoptera: Noctuidae), Aphis gossypii Glover (Hemiptera: Aphididae) or root feeding Tenebrio molitor L. (Coleoptera: Tenebrionidae). Thrips responses to plants simultaneously damaged by 2 species of herbivore were additive and equivalent to the sum of the responses of thrips to plants damaged by single herbivore species feeding alone. For example, F. occidentalis was attracted to T. urticae damaged plants but more attracted to undamaged plants than to plants damaged by H. armigera. Plants simultaneously damaged by low densities of T. urticae and H. armigera repelled F. occidentalis but as T. urticae density increased relative to H. armigera density, F. occidentalis attraction to coinfested plants increased proportionally. Thrips tabaci did not discriminate between undamaged plants and plants damaged by H. armigera but were attracted to plants damaged by T. urticae alone or simultaneously damaged by T. urticae and H. armigera. Olfactometer assays showed that simultaneous feeding by 2 herbivores on a plant can affect predator–prey interactions. Attraction of F. occidentalis to plants damaged by its T. urticae prey was reduced when the plant was simultaneously damaged by H. armigera, T. molitor, or A. gossypii and F. schultzei was more attracted to plants simultaneously damaged by T. urticae and H. armigera than to plants damaged by T. urticae alone. We conclude that plant responses to feeding by 1 species of herbivore are affected by responses to feeding by other herbivores. These plant‐mediated interactions between herbivore complexes affect the behavioral responses of thrips which vary between species and are highly context dependent.     

The Oocysts of Eimeria vermiformis sp. n. and E. papillata sp. n. (Protozoa: Eimeriidae) from the Mouse Mus musclus

SYNOPSIS. Eimeria vermiformis sp. n. and E. papillata sp. n. are described from the mouse Mus musculus. The sporulated oocysts of E. vermiformis are 18–26 by 15–21 μ (mean 23.1 by 18.4 μ); its sporocysts are 11–14 by 6–10 μ (mean 12.8 by 7.9 p). The sporulated oocysts of E. papillata are 18–26 by 16–24 μ (mean 22.4 by 19.2 μ); its sporocysts are 10–13 by 6–9 μ (mean 11.2 by 8.0 μ). A substiedal body is present in E. papillata sporocysts. Patent infections were produced in white laboratory mice with both species. Fourteen species of Eimeria have now been described from the genus Mus.     

Mediation of a plant response to malformin by ethylene

Malformin and ethylene stimulate abscission of the primary leaves of Phaseolus aureus Roxb. in the dark, and abscission stimulation by both compounds is inhibited by indeleacetic acid and CO₂. Ethylene production by malformin-treated buds is stimulated within 4 hours. and up to 8 days, after treatment. Malformin-induced growth disturbances in P. vulgaris L. and abscission in P. aureus are considered mediated by ethylene. Although root curvatures of Zea mays L. are induced by both malformin and ethylene, and malformin is inhibited by CO₂, ethylene production is not stimulated by malformin. A role of ethylene in root curvatures induced by malformin is neither proposed nor disproved.     

Bidirectional Ca2+ coupling of mitochondria with the endoplasmic reticulum and regulation of multimodal Ca2+ entries in rat brown adipocytes

How the endoplasmic reticulum (ER) and mitochondria communicate with each other and how they regulate plasmalemmal Ca²⁺ entry were studied in cultured rat brown adipocytes. Cytoplasmic Ca²⁺ or Mg²⁺ and mitochondrial membrane potential were measured by fluorometry. The sustained component of rises in cytoplasmic Ca²⁺ concentration ([Ca²⁺]_i) produced by thapsigargin was abolished by removing extracellular Ca²⁺, depressed by depleting extracellular Na⁺, and enhanced by raising extracellular pH. FCCP, dinitrophenol, and rotenone caused bi- or triphasic rises in [Ca²⁺]_i, in which the first phase was accompanied by mitochondrial depolarization. The FCCP-induced first phase was partially inhibited by oligomycin but not by ruthenium red, cyclosporine A, U-73122, a Ca²⁺-free EGTA solution, and an Na⁺-free solution. The FCCP-induced second phase paralleling mitochondrial repolarization was partially blocked by removing extracellular Ca²⁺ and fully blocked by oligomycin but not by thapsigargin or an Na⁺-deficient solution, was accompanied by a rise in cytoplasmic Mg²⁺ concentration, and was summated with a high pH-induced rise in [Ca²⁺]_i, whereas the extracellular Ca²⁺-independent component was blocked by U-73122 and cyclopiazonic acid. The FCCP-induced third phase was blocked by removing Ca²⁺ but not by thapsigargin, depressed by decreasing Na⁺, and enhanced by raising pH. Cyclopiazonic acid-evoked rises in [Ca²⁺]_i in a Ca²⁺-free solution were depressed after FCCP actions. Thus mitochondrial uncoupling causes Ca²⁺ release, activating Ca²⁺ release from the ER and store-operated Ca²⁺ entry, and directly elicits a novel plasmalemmal Ca²⁺ entry, whereas Ca²⁺ release from the ER activates Ca²⁺ accumulation in, or release from, mitochondria, indicating bidirectional mitochondria-ER couplings in rat brown adipocytes. plasmalemmal calcium entry; calcium release; mitochondrial depolarization; FCCP     

THE ACTION OF POTASSIUM CYANIDE AND POTASSIUM FERRICYANIDE ON CERTAIN RESPIRATORY PIGMENTS

The oxygen in hemoglobin is liberated by K₃Fe(CN)₆ and not by KCN, that in hemocyanin by KCN and not by K₃Fe(CN)₆, that in hemerythrin by both, and that in echinochrome by K₃Fe(CN)₆ and not by KCN. The bearing of these results on the nature of the substances involved is discussed.     

Reviews of publications

Principles of Crop Improvement, by N. W. Simmonds
Marine Organisms – Genetics, Ecology & Evolution, edited by B. Battaglia & J. A. Beardrnore
Arthropod Phytogeny, edited by A. P. Gupta. Van Nostrand Reinhold
Field Guide to the Land Snails of Britain and North-west Europe, by M. P. Kernev & R. A. D. Cameron; illustrated by Gordon Riley
Key to the Fishes of Northern Europe, by Alwync Wheeler; illustrated by Peter Stebbing; maps by F. Rodney Fraser
Penguin Nature Guides: The Biology of Flowers, by Eigil Holm; illustrated by Thomas BredsdorfT; translated by Joan Tate; edited & adapted by Ronald Melville
Penguin Nature Guides: Orchids of Northern Europe, by Sven Nilsson; illustrated by Bo Mossberg; edited & adapted by P. Francis Hunt
A New Look at the Dinosaurs, by Alan Charig. Heinemann     

Nematophagous Fungi Associated with Root Galls of Rice Caused by Meloidogyne graminicola and its Control by Arthrobotrys dactyloides and Dactylaria brochopaga

Root galls of rice caused by Meloidogyne graminicola were examined for natural colonization by nematophagous fungi from four fields with different nematode infestations. Old galls from severely infested fields had a higher frequency of Monacrosporium eudermatum and Stylopaga hadra than young galls. The frequency of Arthrobotrys oligospora, Arthrobotrys dactyloides, Dactylaria brochopaga and Monacrosporium gephyropagum was lower. A greater proportion (%) of root galls were colonized by nematophagous fungi in those fields in which rice roots had a greater root gall index. This indicated that disease severity supported the colonization of galls by nematophagous fungi. In vitro predacity tests of four fungi showed that A. dactyloides was most effective in capturing and killing J₂ of Mel. graminicola followed by D. brochopaga and Mon. eudermatum. Application of inocula of A. dactyloides and D. brochopaga in soil infested with Mel. graminicola, respectively, reduced the number of root galls by 86% and of females by 94%, and eggs and juveniles by 94%. The application of these fungi to soil increased plant growth: shoot length by 42.7% and 39.8%, root length by 45.5% and 48.9%, fresh weight of shoot by 59.9% and 56.7% and fresh weight of root by 20.3% and 25.1%, respectively, compared to these parameters for plants grown in nematode‐infested soil.     

Reviews of publications

Book reviewed in this article: A World Like Our Own—Man and Nature in Madagascar, by Alison Jolly. Vertebrate Limb Regeneration, by H. Wallace. Statistical Methods in Biology, by N. T.J. Bailey Conservation and Evolution, by O. H. Frankel & M. E. Soule Evolution in Age-structured Populations by B. Charlesworth Essential Biology, by Herbert T. Hendrickson Flora Suzakiensis, edited by Biological Laboratory, Imperial Household Phylogenetic Patterns and the Evolutionary Process, by N. Eldredge & J. Cracraft Excursion Flora of the British Isles, by A. R. Clapham, T. G. Tutin & E. F. Warburg Whales, by W. N. Bonner Les Chevaux, Fossiles et Actuels, by V. Eisenmann Freshwater Snails of Africa and their Medical Importance, by David S. Brown Symbiosis in Cell Evolution, by Lynn Margulis Vegetation Dynamics, by J. Miles     

Influence of Nitrogen Fertilizers on Growth, Spore Production and Germination, and Biocontrol Potential of Trichoderma and Gliocladium

The mycelial weight of eight out of nine isolates of Trichoderma spp. and Gliocladium virens increased in media supplemented with 2000 mg/l of nitrogen (N) from the fertilizers NH₄Cl, NaNO₃, and a commercial 20–20–20. In general, the greatest increase in growth (up to 311 %) occurred with 20–20–20. The extent of growth was similar with either NH₄Cl or NaNO₃, but was less than that with 20–20–20. Measured by radial development on agar surfacesgrowth of isolates was either not affected or was constricted by supplemental fertilizers. Production of conidia by six out of eight isolates was stimulated by 20–20–20 but not by NH₄Cl or NaNO₃. Germination of conidia of all isolates, generally was high (> 85 %) on amended and nonamended agar. Chlamydospore formation by three Trichoderma isolates in liquid media was not affected by fertilizers. Antagonism or overgrowth of the pathogen Rhizoctonia solani by Trichoderma isolates in culture was reduced appreciably by NaNO₃, but was not affected by NH₄Cl or 20–20–20. Addition of 20–20–20 to natural soil did not reduce further the survival of R. solani caused by germling preparations of six out of seven Trichoderma isolates. However, reduction in survival of the pathogen caused by a T. hamatum isolate was stimulated further (45 %) by the fertilizer.     

Effects of structural heterogeneity provided by the floating macrophyte <Emphasis Type="Italic">Eichhornia azurea</Emphasis> on the predation efficiency and habitat use of the small Neotropical fish <Emphasis Type="Italic">Moenkhausia sanctaefilomenae</Emphasis>

Macrophytes have a fundamental structuring role in aquatic environments. Several authors have suggested that trophic interactions are particularly mediated by aquatic plants. In the current article, we evaluated the effects of the structural heterogeneity provided by Eichhornia azurea (Kunth) roots on predation and habitat use by the small fish Moenkhausia sanctaefilomenae (Steindachner). We tested the hypotheses that (i) high structural heterogeneity protects macroinvertebrates against predation by M. sanctaefilomenae; (ii) distinct prey types are differently protected by the refuge provided by roots; and (iii) the behavior of M. sanctaefilomenae is affected by the structural heterogeneity provided by macrophyte roots. To test these hypotheses, we performed an experiment in 20 l aquaria in which macroinvertebrates (Cypricercus sp. and Chironomus sp.) were exposed to M. sanctaefilomenae predation for 4 h under three structural heterogeneities, represented by different root densities. High structural heterogeneity protected macroinvertebrates against predation. Additionally, E. azurea roots similarly protected different prey species. The macrophyte spatial structure substantially changed the habitat use of M. sanctaefilomenae. In general, our results corroborated the hypothesis that the structural heterogeneity provided by E. azurea roots significantly affects predation and habitat use by M. sanctaefilomenae. Handling editor: S. Declerck     

The effect of calcium ions on the glycolytic activity of Ehrlich ascites-tumour cells

1. Added Ca²⁺ inhibited lactate formation from sugar phosphates by intact Ehrlich ascites-tumour cells. Lactate formation from glucose by these cells was unaffected by added Ca²⁺. 2. The Ca²⁺ inhibition of lactate formation by intact cells occurred in the extracellular medium. 3. Intact ascites-tumour cells did not take up Ca²⁺ in vitro. 4. Glycolysis of sugar phosphates by cell extracts as well as pyruvate formation from 3-phosphoglycerate and phosphoenolpyruvate was inhibited by Ca²⁺. 5. It was concluded that Ca²⁺ inhibited the pyruvate-kinase (EC 2.7.1.40) reaction. Further, Ca²⁺ inhibition of pyruvate kinase could be correlated with the overall inhibition of glycolysis. 6. Concentrations of Ca²⁺ usually present in Krebs–Ringer buffers, inhibited glycolysis and pyruvate-kinase activity by approx. 50%. 7. The inhibition of glycolysis by added Ca²⁺ could be partially reversed by K⁺ and completely reversed by Mg²⁺ or by stoicheiometric amounts of EDTA. 8. The hypothesis is advanced that the inability of tumour cells to take up Ca²⁺ is a factor contributing towards their high rate of glycolysis.     

Gene pacA+ codes for the multiple active forms of Pi-repressible acid phosphatase in the mould Aspergillus nidulans

The acid phosphatase secreted by the biA1 strain of the mould Aspergillus nidulans was separated into at least nine isoforms by isoelectric focusing (IEF). The components visualized by activity were predominantly acidic proteins with isoelectric points ranging from pH 4.0 to 6.5. Almost the same isoforms were secreted by strains pabaA1 and palD8 biA1. Furthermore, the isoforms secreted by strain pacA1 biA1 were not visualized by staining after IEF, indicating that these isoforms are encoded by gene pacA. Treatment of the secreted enzyme with endoglycosidase H also reduced the number of isoforms visualized by staining after IEF and enhanced the R_f (electrophoretic mobility) value of this enzyme visualized after PAGE.     

The Effect of Proteolytic Enzymes on E. coli Phages and on Native Proteins

Lambda coli phage is not inactivated by chymotrypsin, trypsin, or ficin. T₂ phage is slowly inactivated by high concentrations of (α-, β-, γ-, or Δ-chymotrypsin, but not by trypsin or ficin. P₁ phage is slowly inactivated by α-, β-, or γ-chymotrypsin, or ficin, more rapidly by Δ-chymotrypsin, and much more rapidly by trypsin. Crystalline egg albumin, crystalline serum albumin, E. coli nucleoprotein, and yeast nucleoprotein are hydrolyzed slowly by α-chymotrypsin. Yeast nucleoprotein, like P₁ phage, is hydrolyzed more rapidly by Δ-chymotrypsin than by α-chymotrypsin, but not by trypsin or ficin. Neither phages nor native proteins were attacked by papain, carboxypeptidase, deoxyribonuclease, or ribonuclease.     

Effects of amino acids and derivatives of cyclic adenosine 3′, 5′-monophosphate on the production of three exoenzymes by Staphylococcus, simulans biovar staphylolyticus

The extracellular protease, endopeptidase, and hexosaminidase produced by $\text{Staphylococcus}\text{,}\text{simulans}\text{biovar}\text{staphylolyticus}$ were neither induced nor repressed by amino acids but required a tryptic digest of casein for their production. Catabolite repression of exoenzyme production by glucose was not affected by exogenous cyclic adenosine 3′, 5′-monophosphate but was partially relieved by di- or monobutyryl derivatives of this compound.     

Inhibition of Iron-oxidizing Activity by Bisulfite Ion in Thiobacillus ferrooxidans

Growth of Thiobacillus ferrooxidans on iron- and sulfur-salts media and iron oxidizing activity of this bacterium were strongly inhibited by bisulfite ion. The mechanism of inhibition by bisulfite ion of iron-oxidizing activity was studied with the plasma membrane of T. ferrooxidans AP19-3. The c-type cytochrome in the plasma membrane was reduced by ferrous ion and the cytochrome reduced by Fe²⁺ was oxidized by cytochrome c oxidase in the plasma membrane. In contrast, c-type cytochrome was reduced by bisulfite ion, but it was not oxidized by cytochrome c oxidase in the membrane. Cytochrome c-oxidizing activity was also inhibited by the ion when mammalian cytochrome c was used as an electron donor, suggesting that cytochrome c oxidase, one of the component of iron oxidase, is the site of inhibition by bisulfite ion.     

Trophic interactions and habitat segregation between competing Daphnia species

Summary Two commonly coexisting species of Daphnia segregate by habitat in many stratified lakes. Daphnia pulicaria is mostly found in the hypolimnion whereas D. galeata mendotae undergoes diel vertical migration between the hypolimnion and the epilimnion. I examined how habitat segregation between these two potentially competing species might be affected by trophic interactions with their resources and predators by performing a field experiment in deep enclosures in which I manipulated fish predation, nutrient levels, and the density of epilimnetic Daphnia. The results of the experiment indicate that habitat use by D. pulicaria can be jointly regulated by competition for food from epilimnetic Daphnia and predation by fishes. Patterns of habitat segregation between the two Daphnia species were determined by predation by fish but not by nutrient levels: The removal of epilimnetic fish predators resulted in higher zooplankton and lower epilimnetic phytoplankton densities and allowed D. pulicaria to expand its habitat distribution into the epilimnion. In contrast, increased resource productivity resulted in higher densities of both Daphnia species but did not affect phytoplankton levels or habitat use by Daphnia. The two species exhibit a trade-off in their ability to exploit resources and their susceptibility to predation by fish. D. g. mendotae (the less susceptible species) may thus restrict D. pulicaria (the better resource exploiter) from the epilimnion when fish are common due to lower minimum resource requirements than those needed by D. pulicaria to offset the higher mortality rate imposed by selective epilimnetic fish predators. D. g. mendotae does not appear to have this effect in the absence of fish.     

Activation of Akt/GSK-3β signaling pathway is involved in intermedin1–53 protection against myocardial apoptosis induced by ischemia/reperfusion

Intermedin (IMD) is a novel member of the calcitonin/calcitonin gene-related peptide family. We investigated the cardioprotective mechanism of IMD_1–53 in the in vivo rat model of myocardial ischemia/reperfusion (I/R) injury and in vitro primary neonatal cardiomyocyte model of hypoxia/reoxygenation (H/R). Myocardial infarct size was measured by 2,3,5-triphenyl tetrazolium chloride staining. Cardiomyocyte viability was determined by trypan blue staining, cell injury by lactate dehydrogenase (LDH) leakage, and cardiomyocyte apoptosis by terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling assay, Hoechst staining, gel electrophoresis and caspase 3 activity. The translocation of mitochondrial cytochrome c of myocardia and expression of apoptosis-related factors Bcl-2 and Bax, phosphorylated Akt and phosphorylated GSK-3β were determined by western blot analysis. IMD_1–53 (20 nmol/kg) limited the myocardial infarct size in rats with I/R; the infarct size was decreased by 54%, the apoptotic index by 30%, and caspase 3 activity by 32%; and the translocation of cytochrome c from mitochondria to cytosol was attenuated. IMD_1–53 increased the mRNA and protein expression of Bcl-2 and ratio of Bcl-2 to Bax by 81 and 261%, respectively. IMD_1–53 (1 × 10⁻⁷ mol/L) inhibited the H/R effect in cardiomyocytes by reducing cell death by 43% and LDH leakage by 16%; diminishing cellular apoptosis; decreasing caspase 3 activity by 50%; and increasing the phosphorylated Akt and GSK-3β by 41 and 90%, respectively. The cytoprotection of IMD_1–53 was abolished with LY294002, a PI3K inhibitor. In conclusion, IMD_1–53 exerts cardioprotective effect against myocardial I/R injury through the activation of the Akt/GSK-3β signaling pathway to inhibit mitochondria-mediated myocardial apoptosis.     

Carrier-Mediated Uptake of Abscisic Acid by Suspension-Cultured Amaranthus tricolor Cells

Abscisic acid (ABA) uptake by Amaranthus tricolor cell suspensions was found to include both a nonsaturable component and a saturable part with K_m of 3.74 ± 0.43 micromolar and an apparent V_max of 1.5 ± 0.12 nanomoles per gram per minute. These kinetic parameters as well as the uptake by intact cells at 0°C or by frozen and thawed cells, are consistent with operation of a saturable carrier. This carrier-mediated ABA uptake was partially energized by ΔpH: it increased as the external pH was lowered to pH 4.0; it decreased after the lowering of the ΔpH by the proton ionophore carbonylcyanide-m-chlorophenylhydrazone or after the altering of metabolically maintained pH gradient by metabolic inhibitors (KCN, oligomycin). The carrier is specific for ABA among the plant growth regulators tested, is unaffected by (RS)-trans-ABA and was inhibited by (S)-ABA, (R)-ABA, and also by the ABA analog LAB 173711.