Effects of free and chelated iron on in vitro androgenesis in barley and wheat

A suitable form of iron supplement in the induction medium was found to be important for further development of induced pollen embryos in barley and wheat cultivars (genotypes), especially those providing few green plants viain vitro androgenesis. Genotypes able to regenerate many green plants were less susceptible to the lack of iron in induction medium. Although Fe-EDTA was found to be a suitable form of iron in the induction medium, androgenesis was also induced on media containing non-chelated iron (Fe²⁺ and Fe³⁺ ions). EDTA alone without iron inhibited the androgenic response even in the wheat cv. Florida, a model cultivar for androgenesis in wheat. In all barley cultivars under study including cv. Igri, a model cultivar for androgenesis in barley, EDTA alone caused an almost total suppression of androgenesis. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cultivation of a desulfurizing bacterium, Mycobacterium strain G3

Various carbon and sulfur sources on the growth and desulfurization activity of Mycobacterium strain G3, which is a dibenzothiophene (DBT)-degrading microorganism, were studied. Ethanol, glucose or glycerol as the sole carbon source and MgSO₄, taurine or dimethyl sulfoxide (DMSO) as the sole sulfur source were suitable for the growth. In addition, desulfurization activity was expressed in medium containing taurine, MgSO₄ or DMSO at 0.1 mM, when 217 mM ethanol was used as the sole carbon source. The highest desulfurization activity was in the stationary phase cells after 5 days' growth, rather than those harvested during active growth, when Mycobacterium G3 was cultivated in medium containing 217 mM ethanol and 0.1 mM MgSO₄. Thus alternative sulfur sources to DBT can be used for the cultivation of this desulfurizing microorganism.     

Protection of catheter surfaces from adhesion of Pseudomonas aeruginosa by a combination of silver ions and lectins

A catheter surface was modified by coating a cellulose acetate polymer. Adhesion of Pseudomonas aeruginosa ATCC 27853 to the surface was investigated by exposing bacterial cultures to three treatments: polymer impregnated with silver ions (Ag⁺), polymer surfaces coated with lectins and a combination of Ag⁺ and a lectin coating. The effective concentration of Ag⁺ providing protection against bacterial biofilm development was 100g/ml and higher. Lectins alone at 10% also showed inhibition of bacterial attachment. However, the best result was achieved against bacterial adhesion and growth on surfaces using a combination of 100 g Ag⁺/ml and a lectin coating as a surface treatment. This surface treatment was also effective against both fresh culture and a two-week-old culture containing P. aeruginosa producing exopolymers. Our results suggest that Ag⁺impregnation combined with a lectin coating warrants further investigation as a potential means of protecting catheters.     

Dynamics of inorganic ions in microspore and pollen grain during development of the tobacco male gametophyte

We studied the dynamics of mobile potassium, chloride, and nitrate ions during development of the microspore and differentiation of the pollen grain inNicotiana tabacum L. by measuring their concentration in aqueous extracts from cells destroyed by freezing-thawing using ion-selective electrodes. Stage-specific changes in the ion content and intracellular concentration in the male gametophyte were found. A relationship of the dynamics of ions to growth processes and changes in metabolic activity during gametophytogenesis has been discussed. The changes in the potassium and chloride ion concentrations have been interpreted as regulatory changes controlling protein synthesis in the pollen grain vegetative cell. Deceased.     

耐镉甲基营养芽胞杆菌吸附条件的优化及其抗逆性

【目的】对所筛选的1株耐镉甲基营养芽胞杆菌NTGB29进行了环境抗逆性的研究,及影响菌株吸附镉离子效率的条件优化。【方法】以发酵液活菌数为指标,研究其对不同NaCl浓度、酸碱度、镉离子浓度的耐受情况;进一步通过单因素实验和响应面法优化影响菌株镉离子吸附效率的发酵条件;以有效镉离子含量为指标,验证菌株在镉污染土壤中的吸附效果。【结果】结果表明,菌株NTGB29对NaCl浓度、酸碱度、Cd~(2+)浓度的最大耐受值分别为10%、pH11.0、50mg/L;菌株在发酵液初始Cd~(2+)浓度10 mg/L、起始pH 6.4、培养温度37°C、NaCl浓度4.2%、装液量50 mL/250 mL、培养时间24 h时,对Cd~(2+)的吸附率达到79.70%;菌株能有效降低镉污染土壤中的有效镉离子含量,吸附率为29.65%。【结论】菌株NTGB29在较高浓度Cd~(2+)浓度、NaCl浓度及强碱环境条件下仍然能够生长,具有良好的环境抗逆性及Cd~(2+)吸附能力,在镉污染土壤调理剂及微生物功能菌剂的研制方面能够提供有价值的菌种资源。     

Effect of malathion exposure on some physical parameters of whole body and on tissue cations of teleost,Tilapia mossambica (Peters)

Exposure of fish to a sublethal (2 mg/litre/48h) concentration of malathion showed no significant changes in any of the physical parameters investigated like, body weight and body water content, while the oxygen consumption of the fish showed a consistent increase upto 24 h and later declined to 8% suggesting the reduction of oxidative metabolism at the end of 48 h. The sodium, potassium and calcium ions showed a remarkable decrease in all the tissues of malathion-exposed fish, suggesting the loss of ions from the body of these fish. The results suggested that the regulation of osmotic balance may occur by an effective operation of the salt pump rather than the water pump.     

Nucleotide pyrophosphatase/phosphodiesterase from Euphorbia characias latex: Purification and characterization

An authentic soluble metallo-protein nucleotide pyrophosphatase/phosphodiesterase (ELNPP) was purified to homogeneity from Euphorbia characias latex. The native protein had a molecular mass of 80 ± 5 kDa and was shown to be formed by two apparently identical subunits, each containing 1 Ca²⁺ and 1 Mg²⁺ ion. Whereas Mg²⁺ was shown to be strongly bound to the enzyme, Ca²⁺ was easily removed by treatment with EDTA. Ca²⁺-demetalated enzyme was shown to be almost totally inactive and the activity was fully restored incubating the demetalated ELNPP with Ca²⁺ ions. ELNPP exhibited hydrolytic activities toward pyrophosphate/phosphodiester bonds of a broad range of substrates and very efficiently hydrolyzed the artificial substrate thymidine 5′-monophosphate 4-nitrophenyl ester generating 4-nitrophenolate as a final product, and it has been used for enzyme kinetic experiments. ELNPP represents the first example of a nucleotide pyrophosphatase/phosphodiesterase enzyme purified from the latex of a plant belonging to the large genus Euphorbia.     

Ionenabhängige Keimungsaktivierung der Sporangiosporen vonPhycomyces blakesleeanus undP. nitens,demonstriert an verschiedenen Stämmen

Zusammenfassung Es wurde der Einfluß der Kationen Na⁺, K⁺, Ca²⁺ und NH ₄ ⁺ in Verbindung mit dem Anion Acetat auf die Keimungsrate einigerPhycomyces-Stämme (P. blakesleeanus 1+, 2-, 11+ und 18- Sammlung Halbsguth; 188+ und 189-Sammlung Baarn;P. nitens 304+ und 305-Sammlung Baarn) hin untersucht. Es konnte gezeigt werden, daß den Kationen eine wesentliche Rolle im Aktivierungsprozeß zukommt. Förderlich wirkten sich vor allem K⁺ und Ca²⁺ Ionen aus. NH ₄ ⁺ wies keine sichtbar fördernde Wirkung auf, und dem Na^- Ion kann eine hemmende Wirkung im besonderen für dieP. blakesleeanus-Stämme 2-, 188+, 189- zugeschrieben werden. Eine vergleichbar empfindliche Reaktion zeigteP. nitens gegenüber Ca²⁺-Ionen, jedoch nur, wenn höhere Konzentrationen verwendet wurden. Allgemein waren dieP. nitens-Stämme 304+, 305- in ihrer Aktivierbarkeit nicht in dem Maße von den einzelnen Kationen abhängig wie dieP. blakesleeanus-Stämme.Ferner wurde die Wirkung der Wärmeaktivierung auf die Sporenkeimung geprüft. Die günstigste Dauer der Wärmeaktivierung bei 50°C lag für dieP. blakesleeanus-Stämme bei 5 min; dieP. nitens-Stämme vertrugen noch eine Zeit von 40 min (50°C) ohne erkennbare Schädigung.Die Aktivierbarkeit der Sporangiosporen in Abhängigkeit vom Aktivierungsagens (Acetat bzw. Wärme) zeigte deutliche Unterschiede zwischen denP. blakesleeanus- undP. nitens-Stämmen.

---

Activating of germination dependent on lons of sporangiospores ofPhycomyces blakesleeanus andP. nitens, demonstrated on various strains

The influence of cations Na⁺, K⁺, Ca²⁺ and NH ₄ ⁺ in connection with anion acetate on the rate of germination was studied for severalPhycomyces strains (P. blakesleeanus 1+, 2-, 11+, 18- collection Halbsguth; 188+, 189- collection Baarn;P. nitens 304+ and 305- collection Baarn). Cations played an important role during the activating process; NH ₄ ⁺ did not further the effect. The Na⁺ ion inhibited. The inhibition was marked onP. blakesleeanus strains 2-, 188+ and 189-. A comparable sensitive reaction ofP. nitens was apparent towards Ca²⁺ ions, when higher concentrations were used. Generally activations ofP. nitens strains 304+ or 305- were not influenced by the different cations as much as were theP. blakesleeanus strains.Furthermore the effect of heat activation on spore germination was tested. The most favourable time period for heat activation at 50°C was 5 min for theP. blakesleeanus strains, while theP. nitens strains tolerated a period of 40 min at 50°C without any detectable damage (90% germinated spores).The ability ofPhycomyces sporangiospores to be activated showed differences between theP. blakesleeanus andP. nitens strains depending on the activating agent (heat or acetate).

     

Electrohydrodynamic effects on two species of insects with economic importance to stored food products

An electrohydrodynamic (EHD) system which generated air ions within a strong electric field was used to study responses of stored-product insectsTribolium confusum (du Val) andPlodia interpunctella (Hübner). Larval mortality of both species generally increased with increased exposure time to ions of either polarity. The larvae and pupae ofT. confusum suffered a higher mortality rate than the adults. The insects initially exhibited distinct avoiding motions away from regions of high towards low fluxes of air ions of both polarity. Insects moved vigorously, tumbled, flipped, curled up, and aggregated when the EHD system was turned on. The control insects not exposed to air ions survived and showed a total absence of such behaviour. For bipolar exposures, the insects occupied the neutral zone where the effects were minimal due to cancellation of the fields. Prolonged exposures of more than 20 min produced a quiescent state. EHD-enhanced mass transfer of the liquid component from physical objects established in fluid mechanics was invoked as a possible cause for insect mortality and avoiding behaviour to ions. Body fluid losses increased linearly with time of exposure (R ²0.97) for all biological stages of insect growth. The larvae and pupae ofT. confusum lost 12 and 15% of their body fluids, respectively, after 80 min of exposure to negative air ions. Fluid losses of such a magnitude are likely to have contributed to insect fatality.     

Growth characteristics and ion contents of non-selected and salt-selected callus lines of highbush blueberry (Vacdnium corymbosum) cultivars Blue Crop and Denise Blue

Non-selected and sodium chloride selected callus lines of Vacdnium corymbosum L.cv Blue Crop and cv. Denise Blue were grown on media supplemented with 0–100 mM NaCl. For both cultivars, fresh weight and dry weight yields were greater in selected lines on all levels of NaCl. Selected lines of Blue Crop displayed better growth than selected lines of Denise Blue at most concentrations of NaCl. Internal Na⁺ and Cl^– concentrations in selected and non-selected lines of both cultivars increased as external concentration was raised. However, selected lines of Blue Crop and Denise Blue accumulated more Na⁺ and Cl^– than non-selected lines. Selected lines of both cultivars maintained higher levels of K⁺ than non-selected lines on all external NaCl levels. Selected lines of Blue Crop had higher levels of Na⁺ and Cl^– than that of Denise Blue. The results suggest Na⁺ and Cl^– accumulation could be a mechanism allowing better growth in selected lines at moderate salinity levels (50–75 mM NaCl).     

Technical communication: Determination of cuprous ions in bacterial leachates and for environmental monitoring

A sensitive and precise spectrophotometric method has been developed for the determination of copper(I) in bacterial leach liquors produced by the action of Thiobacillus ferrooxidans and T. thiooxidans on copper ores. In this method bicinchoninic acid (BCA) has been used as the chromogenic reagent which produces a stable purple complex with Cu(I) which was found to obey Beer's Law and with _max at 560 nm. The coloured complex has a molar extinction coefficient () value of 6.6 × 10³ l mol^–1 cm^–1; specific absorptivity () value of 0.104 ml^–1 g cm^–1 and the Sandell sensitivity (S) value was 0.0096 g cm². Optimal conditions for development of coloration/sensitivity were determined. Interferences due to cations and anions were investigated and various masking agents for alleviating their inhibition were studied. The method has been found very useful in determining ratios of Cu(I) to Cu(II) in bacterial leach liquors and should play a significant role in determining the reaction mechanisms of biological leaching and for environmental monitoring.     

The uptake of copper ions by cell suspension cultures of Agave amaniensis,and its effect on the growth,amino acids and hecogenin content

Cell suspension cultures of Agave amaniensiswere able to grow in media containing 10 – 240 M copper ions, and could remove more than 67% copper ions from the media. The cells accumulated up to 106 mg g^–1 copper ions in the biomass. Copper ions at 240 M caused a decrease in growth index and packed cell volume of the cultures of 61.5 and 53.3%, respectively. The presence of copper ions caused the cell walls to thicken and to be more wrinkled. Certain amino acids were released in high concentration into the media. The hecogenin content in the biomass increased up to 157.9% at 20 M copper ions.     

Effect of some heavy metal ions on copper-induced metallothionein synthesis in the yeast Saccharomyces cerevisiae

Copper-induced metallothionein (MT) synthesis in Saccharomyces cerevisiae was investigated in order to associate this exclusively with Cu²⁺ in vivo, when cultured in nutrient medium containing other heavy metal ions. Expression of the CUP1 promoter/lacZ fusion gene was inhibited by all heavy metal ions tested, especially Cd²⁺ and Mn²⁺. By adding Cd²⁺ and Mn²⁺ at 10 M concentration, the -galactosidase activity decreased by about 80% and 50% of the maximum induction observed with 1 mM CuSO₄, respectively. Furthermore, cell growth was markedly inhibited by combinations of 1 mM-Cu²⁺ and 1 M-Cd²⁺. Therefore, the yeast S. cerevisiae could not rely on MT synthesis as one of the copper-resistance mechanisms, when grown in a Cd²⁺ environment. In contrast, the presence of Mn²⁺ in the nutrient medium showed alleviation rather than growth inhibition by high concentrations of Cu²⁺. The recovery from growth inhibition by Mn²⁺ was due to decreased Cu²⁺ accumulation. Inhibitory concentrations of Co²⁺, Ni²⁺ and Zn²⁺ on expression of the CUP1p/lacZ fusion gene were at least one order of magnitude higher than that of Cd²⁺ and Mn²⁺. These results are discussed in relation to Cu²⁺ transport and Cu-induced MT synthesis in the copper-resistance mechanism of the yeast S. cerevisiae.     

A novel method for in vitro culture of plants: Cultivation of barley in a floating hydroponic system

We describe a system for hydroponically growing plants that is based on using a polyethylene (PE) granulate as the floating body. The procedure can be performed in all suitable vessels (e.g., bowls, basins, glasses) and is independent of the culture area. Barley plants (Hordeum vulgare) grown in this hydroponic system had no difference in the uptake of mercuric and cadmium ions when compared with plants grown on a defined agar medium. The simple and inexpensive method can be used for the isolation of leaf tissue and large amounts of root tissue. In addition, numerous experiments can be run in parallel.     

Sodium ions are necessary for growth and energy transduction in the marine cyanobacterium Oscillatoria brevis

The maximal growth rate of the marine cyanobacterium Oscillatoria brevis was reached at 200–400 mM NaCl and pH 9.0–9.6. NaCl was found (i) to stimulate the rate of the light-supported generation across the cytoplasmic membrane of the cells and (ii) to decrease the sensitivity of level and motility of the O. brevis trichomes to protonophorous uncouplers. The Na⁺/H⁺ antiporter, monensin, increased both and the uncoupler sensitivity of the cells. The data obtained agree with the assumption that O. brevis possesses a primary Na⁺ pump in its cytoplasmic membrane.Abbreviations ATP adenosine-5-triphosphate - TTFB tetrachlortrifluoromethylimidazol - CCCP carbonyl cyanide m-chlorophenylhydrazone - Na⁺ transmembrane electrochemical potential differences of Na⁺ - transmembrane electric potential difference - pNa transmembrane pNa difference     

Histological and electron microscopical observations on the effects of different salinities and heavy metal Ions,on the gills of Jaera nordmanni (Rathke) (Crustacea,Isopoda)

Summary The effects of different salinities and concentrations of copper, mercury and cadmium ions on the gills of Jaera nordmanni are investigated by means of light and electron microscopy. After exposure to 10% and 50% sea water the gill epithelium cells show a marked uniformity in appearance, possessing characteristically large, sub-cuticular spaces which are prominent between microvilli. With exposure to the heavy metal ions a similar sequence of histological and ultrastructural changes occur in all the gill epithelial cells, culminating in cell breakdown. The ultrastructural changes include distended microvilli, dilated endoplasmic reticulum, dissociated ribosomes, diffuse (swollen) cytoplasm, swollen mitochondria and a basal membrane withdrawn from the basal lamina. An increase in the number of haemocytes is also commonly observed in the haemolymph spaces during heavy metal ion exposure. The significance of the morphological changes undergone by the gill epithelial cells after exposure to different salinities and heavy metal ion concentration, are discussed in relation to the physiological functioning of the gill.The author wishes to thank Dr. M.B. Jones and Mr. R.H. Moore for setting up the experiments and to Professor E. Naylor for providing laboratory facilities at the Department of Marine Biology, University of Liverpool, Port Erin, Isle of Man. This work was supported by a Ministry of Defence (Navy) Contract No. AT/2198/010/CDL.     

Humid acid influence on the growth and copper tolerance of chlorella sp.

The authors describe and discuss experiments carried out withChlorella sp. in which the effect of humic acid on its growth was studied. Also the coupled effect of humic acid and tolerance to cupric ions was demonstrated. Some ecological implication are discussed.