Effect of mammogenic hormones on the expression of dFGF7, FGF10 and their receptor in mouse mammary gland

To investigate the regulation of estrogen, progesterone and prolactin stimulating the development of mammary gland, the Kunming mice were used as experimental animals in this study.Through the ex-periment in vitro, the effect of mammogenic hormones were systematically investigated on expression of FGF7 and FGF10 and their receptor in different periods.The results are as follows:in mammary glands of mice, 17 beta-estradiol increased the expression of FGF7;progesterone did not affect the expression of FGF7;prolactin up-regulated the expression of FGF7 significantly in pregnancy and lac-tation.17 beta-estradiol increased the expression of FGF10;progesterone and prolactin reduced the expression of FGF10 significantly in virgin;prolactin significantly increased the expression of FGF10 in pregnancy.When 17 beta-estradiol in the body was in relatively high proportion, it would lower the ex-pression of KGFR;while 17 beta-estradiol in the body was in relatively low proportion, it would increase the expression of KGFR.Low concentration of progesterone increased the expression of KGFR and high progesterone did not affect the expression of KGFR.Prolactin increased the expression of KGFR significantly in pregnancy and lactation.     

Simulations of tokamak discharges with fast L-H transitions

Results are presented from the simulations of discharges with fast L-H transitions in the JET tokamak. During a transition, electron temperature perturbations propagate into the plasma core over a time much shorter than the transport time characteristic of this device. It is shown that the experimentally observed variations in the electron temperature may be caused by the change in the particle source intensity in the plasma when the atomic flux decreases, which is detected from the drop in the intensity of the D_α hydrogen spectral line. Hence, the experiments under consideration can be explained without the assumption about the nonlocal character of transport processes in tokamaks, which was made in some papers devoted to JET experiments. The plasma component responsible for the apparent nonlocal character of transport processes is the neutral component, whose propagation time across the plasma column is sufficiently short (t<100 μs). __________ Translated from Fizika Plazmy, Vol. 28, No. 1, 2002, pp. 3–8. Original Russian Text Copyright ? 2002 by Leonov.     

Selenium levels in human plasma and hair in northern poland

The aim of this study was to (1) estimate the concentration of selenium in the plasma of 146 residents (65 men and 81 women) and in the hair of 34 persons from the Gdańsk region in northern Poland, aged 19–70 and (2) compare the obtained results with data corresponding to healthy populations living in different European countries. Selenium in plasma was determined by atomic absorption spectrometry using the hydride generation method. The mean selenium concentration in plasma of the investigated persons was 73.3 ± 14.1 μg/L, 76.7 ± 13.2 μg/L in men, and 70.4 ± 14.7 μg/L in women. No age — dependent differences in plasma selenium were found in the investigated population. In 20% of the investigated persons, the selenium level in plasma was lower than 60 μg/L. The mean selenium concentration in hair was 0.30 ± 0.11 μg/g. A positive, statistically significant correlation between selenium concentrations in the plasma and hair of the investigated persons was found. The obtained results indicate that the selenium level in significant part of this population is suboptimal and should be elevated by supplementation with this element.     

Soil salt and nutrient concentration in the rhizosphere of desert halophytes

North-West China is an arid region where halophyte plants are rich. Very little is known on the rhizospheric soil of the halophytes in this arid desert region. We conducted a rhizobag experiment on the desert Solonchak soil to investigate the salt and nutrient content in the rhizospheric soil of the desert halophytes. The total salt and the concentrations of 8 major kinds of salt ions increased in the rhizosphere of both succulent halophytes and salt secreting halophytes, but this increase was insignificant for salt-resisting halophytes. Accumulation of Cl^– and Na⁺ is the most significant among the 8 major kinds of salt ions. Accumulation of Cl^– was more significant than that of SO₄^2– in succulent halophytes and salt secreting halophytes. The Na⁺/K⁺, Na⁺/Ca²⁺ and Na⁺/Mg²⁺ ratios in the rhizosphere of all 7 kinds of halophytes were higher than those in the bulk soil. Total N increased significantly in the rhizosphere, but total P and total K decreased. However, the available N, P and K in the rhizosphere of the 7 kinds of halophytes except Phragmites communis Trin. behaved in such an opposite way that available N decreased but available P and available K increased. The ionic contents in the aboveground parts were higher than those in the underground parts of the 7 kinds of halophytes, in particular of both the succulent halophytes and the salt secreting halophytes. Accumulation of Cl^– and Na⁺ in the aboveground parts of the plants was the most significant among that of the 8 major kinds of salt ions.     

Cell Aggregation in Cultures of <Emphasis Type="Italic">Micrococcus luteus</Emphasis>, Studied by Dynamic Light Scattering

Cell aggregation was studied using the method of dynamic light scattering in the course of growth of Micrococcus luteus cultures in a liquid medium. The method detects particles ranging in size from 0.5 to 1000 μm in samples containing no more than 10⁵ cells/ml. When grown in liquid media, M. luteus forms aggregates; during the lag phase, 80% of the cells are found in aggregates of 10–1000 μm, only minor amounts being represented by single cells. With the onset of exponential growth, the aggregates were decomposed and single cells became prevalent in the culture liquid. This observation confirms that the aggregation of the cells during the lag phase is prerequisite to the initiation of bacterial growth. The method may be used in biotechnology for monitoring the state of bacterial cultures. __________ Translated from Prikladnaya Biokhimiya i Mikrobiologiya, Vol. 41, No. 6, 2005, pp. 647–651. Original Russian Text Copyright ? 2005 by Voloshin, Kaprelyants.     

Refined structure of basic phospholipase A2 from venom of Agkistrodon halys Pallas in orthorhombic crystal form I at 0.25 nm resolution

The basic phospholipase A2 from the venom of Agkistrodon halys Pallas is a potent hemolytic toxin and anticoagulant. The accurate rotation and translation parameters of the molecules in orthorhombic crystal form I were successfully obtained using the fitting refinement technique. The structure was refined in the resolution range of 0. 6-0.25 nm using least square refinement with non-crystallographic two fold symmetry restraint, and resulted in the final R factor of 20.1 % , and the rms deviations from ideal stereochemistry were 0. 001 3 nm for bond lengths and 1. 32° for bond angles. The overall architecture of the present structure was similar to that of the determined structure of the orthorhombic crystal form Ⅱ, with a few differences in the regions of the β-wing and Ca²⁺-binding loop. The dimers formed by the two molecules in the asymmetric unit in both crystal forms were also similar. However, one of the monomers showed an orientational difference of 5.5° along the dimer interface in the two crystal forms, suggesting the flexibility of the interface of the dimer to some degree. The molecular packing of the dimer in crystal form I was much more compact than that in crystal form Ⅱ.     

Experimental Visualization of Chromoneme as a Higher Level of Chromatin Compactization in the Mitotic Chromosome

We succeeded to visualize the chromoneme or a filamentous chromatin structure, with the mean thickness 0.1–0.2 μm, as a higher level of chromatin compactization in animal and plant cells at different stages of chromosome condensation at mitotic prophase and during chromatid decondensation at telophase. Under the natural conditions, chromoneme elements are not detected in the most condensed chromatin of metaphase chromosomes on ultrathin sections. We studied the ultrastructure and behavior of the chromatin of mitotic chromosomes in situ in cultured mouse L-197 cells under the conditions selectively demonstrating the chromoneme structure of the mitotic chromosomes in the presence of Ca²⁺. Loosely packaged dense chromatin bands, ca. 100 nm in diameter, chromonemes, were detected in chromosome arms in a solution containing 3 mM CaCl₂. When transferred in a hypotonic solution containing 10 mM tris-HCl, these chromosomes swelled, lost the chromoneme level of structure, and rapidly transformed in loose aggregates of elementary DNP fibrils, 30 nm in diameter. After this decondensation in the low ionic strength solution, the chromoneme structure of mitotic chromosomes was restored when they were transferred in a Ca₂₊ containing solution. The morphological characteristics of the chromoneme and pattern of its packaging in the chromosome were preserved. However, when the mitotic cells with chromosomes, in which the chromoneme structure was visualized with the help of 3 mM CaCl₂, were treated with a photosensitizer, ethidium bromide, and illuminate with a light with the wavelength 460 nm, chromatic decondensation under the hypotonic solution was not observed. The chromoneme elements in a stabilized chromatin of the mitotic chromosome preserved specific interconnection and the general pattern of their packaging in the chromatid was also preserved. The chromoneme elements in the chromosomes stabilized by light preserved their density and diameter even in a 0.6 M NaCl solution, which normally leads to chromoneme destruction. An even more rigid treatment of the stabilized chromosomes with a 2 M NaCl solution, which normally fully decondenses the chromosomes, made it possible to detect a 3D reticular skeleton devoid of any axial structures. __________ Translated from Ontogenez, Vol. 36, No. 5, 2005, pp. 323–332. Original Russian Text Copyright ? 2005 by Burakov, Tvorogova, Chentsov.     

Distribution,biomass and production of Gracilaria in Lüderitz Bay,Namibia

The extent and biomass of the Gracilaria beds in the Lüderitz Bay area, Namibia were surveyed in winter and summer. The beds covered most of the suitable sediments available (grain size 106–212 μm) and did not occur in water shallower than 1 m or deeper than 11 m. Total surface area, most of which occurred in the Bay system, changed very little from winter to summer but biomass increased by 3.5 fold. In winter, total Gracilaria biomass was 200 t and 650 t and in summer, 150 t and 2850 t respectively in the Lagoon and Bay. Maximum biomass occurred at 3–4 m in the Lagoon and 5–6 m in the Bay in both winter and summer. Gracilaria beach cast data from 1987 to 1991 for the area were analysed for seasonality and, depending on the specific site, correlated with swell, southerly wind velocity and sea temperature. Beach cast in the Lagoon system is a more continuous process than in the Bay, where beach casts at most sites follow an annual pattern. Wind driven currents and chop were the most important causative parameters of beach cast in the Lagoon whereas the depth at which the plants were growing and swell were more important in the Bay system. The two systems viz. Lagoon and Bay are independent of one another with very little or no exchange of Gracilaria between them. This was evidenced by the similar percentage each contributes to the total beach cast and the similar pattern of beach cast from year to year. The decrease in total beach cast from 1989 to the end of the study period was attributed to a trend towards increasing swell height and low sea temperatures in 1991.     

Accumulation and detoxification of cadmium in <Emphasis Type="Italic">Brassica pekinensis</Emphasis> and <Emphasis Type="Italic">B. chinensis</Emphasis>

The effect of excessive Cd on the growth and metal uptake by leafy vegetables Brassica chinensis L. (cv. Wuyueman) and Brassica pekinensis (Lour.) Rupr. (cv. Qingyan 87-114) were studied in hydroponic solution culture. The Cd concentration higher than 10 μM significantly decreased the root elongation and leaf chlorophyll contents of both plant species. The shoots of B. pekinensis had significantly higher concentrations of total and water-soluble Cd than B. chinensis. The roots of both species accumulated more Cd than the shoots in all the Cd treatments. Most of the Cd in the roots was found in the cell walls. The shoot/root ratio of Cd concentrations in B. pekinensis was always greater than that in B. chinensis. But, the concentration and proportion of Cd in the cell walls in B. chinensis were higher than that in B. pekinensis. Cadmium treatments also increased the concentrations of total non-protein thiols (NPT) in the shoots of the both species. A significant correlation was found between the concentrations of soluble Cd and NPT in plant shoots.     

Gradient of photosynthetic pigments in the bark and leaves of lilac (Syringa vulgaris L.)

The concentration of chlorophyll and a carotenoids in the bark of stems of different age and in the leaves of lilac (Syringa vulgaris L.) was determined. The thickness of bark changes with the age of the stems, ranging from 0.73 mm in the current-year stems to 1.22 mm in 3-year-old ones. Chlorophyll and carotenoids were present through the whole thickness of the bark, except the cork. It was found that chlorophyll and carotenoids are located mainly in the outer layer of the bark, immediately under the cork, to a depth of 400 μm. In this layer the chlorophyll a/b ratio is the highest and the content of chlorophyll is four times larger than that of carotenoids. When penetrating deeper into the bark, the content of chlorophyll and carotenoids as well as the chlorophyll a/b ratio diminishes. Investigations of the leaves showed that most of the chlorophyll is found in the palisade parenchyma, the chlorophyll a/b ratio is the highest in the upper layer. The highest concentration of chlorophyll in the bark is 0.44 mg·dm⁻² and in leaves −1.2 mg⁻²·dm⁻². The highest value of the chlorophyll a/b ratio in the bark is 3.8, and the lowest 0.5, while in the leaves it varies from 4.5 to 3.8 Low values of the chlorophyll a/b ratio are due to the shade conditions existing in the bark and they are evidence of very great differentiation of light conditions within it.     

Increase in the CO2 exchange rate of leaves of Ilex rotunda with elevated atmospheric CO2 concentration in an urban canyon

 It was found that the atmospheric carbon dioxide (CO₂) concentration in an urban canyon in Fukuoka city, Japan during August 1997 was about 30 μmol mol⁻¹ higher than that in the suburbs. When fully exposed to sunlight, in situ the rate of photosynthesis in single leaves of Ilex rotunda planted in the urban canyon was higher when the atmospheric CO₂ concentration was elevated. A biochemically based model was able to predict the in situ rate of photosynthesis well. The model also predicted an increase in the daily CO₂ exchange rate for leaves in the urban canyon with an increase in atmospheric CO₂ concentration. However, in situ such an increase in the daily CO₂ exchange rate may be offset by diminished sunlight, a higher air temperature and a lower relative humidity. Thus, the daily CO₂ exchange rate predicted using the model based soleley on the environmental conditions prevailing in the urban canyon was lower than that predicted based only on environmental factors found in the suburbs. Received: 24 October 1997; Received after revision: 25 March 1998; Accepted: 1 June 1998     

Formation of spicules by sclerocytes from the freshwater spongeEphydatia muelleri in short-term cultures in vitro

Summary Cells from the freshwater spongeEphydatia muelleri were isolated by dissociating hatching gemmules. During the first 24 h the cells reaggregated, but the aggregates progressively disintegrated again to single cells, among which the spicule-forming sclerocytes were recognized. Such cultures were used to study spicule (megascleres) formation in vitro. The isolated sclerocytes formed the organic central axial filament onto which they deposited inorganic silicon. The size of the spicules (200 to 350μm in length) as well as the rate of spicule formation (1 to 10μm/h) under in vitro conditions were similar to the values measured in vivo. Immediately after completion of spicule formation, or even before, the sclerocyte could start formation of a new spicule; 5% of the cells were in the process of forming two spicules simultaneously. Cultivation of sclerocytes in the absence of silicon resulted in the formation of the axial filament only. We succeeded in maintaining the sclerocytes in a proliferating and spicule-forming state for up to 3 mo. These results demonstrate that the establishment of short-term cell cultures fromE. muelleri is possible; however, future studies must be undertaken to identify the growth factors required for a permanent culture of sponge cells.     

Side effects of water liming on body size and eggs development of Daphnia species in Lake Orta (N. Italy)

Life-tables of the Daphnia species (D. longispina and D. obtusa), currently inhabiting the previously acidified Lake Orta, were followed to study the side effects of liming on the demographic parameters (e.g. longevity, body size increment, eggs and new-borns production), of both species. Different media were prepared to simulate the lake water pH's (5, 6 and 7), and copper concentrations (40 μg l^-1), before and after liming, using GF/C filtered lake water in such simulation and as a reference medium. The obtained results have shown that, the individuals of D. longispina were only able to survive after the liming and the consequent reduction in copper concentrations. However, due to shift occurred in the different media pH's after liming toward slightly alkaline conditions, no significant variations in body size increment or in eggs and newborns production were detected of this species in the different media (p = 0.38, p = 0.29, p = 0.09 respectively). On the other hand, the effect of the variations in pH on the body size increment of the B. obtusa individuals was marginally significant (p = 0.07). A highly significant (p = 0.002), increase in eggs production by D. obtusa individuals was detected in the different media after the CaCO₃ addition. Conversely, a corresponding highly significant (p = 0.0007), decrease in the production of new-borns, accompanied by the degeneration of about 78% of the produced eggs, was detected in the different media after liming. Our results suggest that in Lake Orta the actual irregular abundance of the studied Daphnia species and the eggs degeneration phenomenon, observed in our study, could be largely attributed to the interspecific competition resulting from species-specific sensitivity to the continuous variations in the lake water Chemistry after the liming operation. This revised version was published online in July 2006 with corrections to the Cover Date.     

Latitudinal changes in species diversity of permafrost wetland plant communities in Great Xing’an Mountain valleys of Northeast China

Studying the changes of species diversity in plant communities along latitude gradients is important to discover the correlation between biodiversity and environmental factors. Along the main ridges of the Great Xing’an Mountains, 12 natural permafrost wetlands in the valleys were investigated from north to south. Latitudinal changes in species diversity were analyzed with regressive analysis. About 150 plant species were recorded and were found to be in the 12 permafrost wetland plant communities. Most plants belong to the Compositae or Gramineae. The number of family, genus and species increased significantly in the herb layer with decreasing latitude (P < 0.01), but decreased significantly in the shrub layer (P < 0.01). Species composition and the orders of dominant species in the plant communities by importance value changed along latitude. Latitudinal changes of α-diversity in permafrost wetland plant communities were different in the herb and shrub layers. With decreasing latitude, species richness and species diversity increased in the herb layer; but decreased in the shrub layer. The opposite patterns were found for species dominance. Species evenness in the shrub layer decreased with decreasing latitude. ?-diversity in the herb and shrub layers decreased first, and then increased, and finally decreased with increasing latitude. Species composition in the herb layer was similar among the plots at higher latitudes.     

Prolonged Growth of Young Spruce (<Emphasis Type="Italic">Picea koraiensis</Emphasis> Nakai) Plants at Double Atmospheric CO<Subscript>2</Subscript> Concentration Stimulates the Preferential Growth of Thick Roots

Two-year-old young spruce (Picea koraiensis Nakai) plants were grown in a climatic chamber during three summer months at double atmospheric CO₂ concentration, sufficient content of soil inorganic nitrogen, and diurnal variation of temperature and illuminance, which simulate natural growth conditions. The control plants were grown in another climatic chamber under the same conditions, but at atmospheric CO₂ concentration (350 ppm). CO₂ exchange was measured with a Li-Cor 6400 infra-red gas analyzer in attached leaves placed in a climatic chamber in the morning under growth conditions and saturating light 1200 μE/(m² s) in June, July, and August. In addition, dry weights of needles, leafless shoot parts of plant, fraction of thick (more than 0.5 mm in diameter) and thin (less than 0.5 mm in diameter) roots were recorded. The data were used to plot CO₂ exchange rates as a function of carbon dioxide concentration and to calculate the increment of shoot and root phytomass. The maximum gas exchange rates in the treated and control plants similarly depended on CO₂ concentration. The slope of the CO₂ dependence curve, which corresponded to the kinetic characteristic V _m /K _M of photosynthetic carboxylation, increased monotonically during the experiment. To the end of observation period, the proportion of thick roots in plant phytomass significantly increased in the plants grown at double atmospheric CO₂ concentration, as compared to the control plants. Thus, the increase in the rate of photosynthetic gas exchange in plants grown for three months at double atmospheric CO₂ concentration was only due to the increase in CO₂, the substrate of Rubisco carboxylation activity. We found no differences in the CO₂ characteristic for Rubisco between the treated and control plants. The ratio of needle to thin roots in the treated and control plants was similar and did not change during the experiment. The excess of photoassimilates in the treated, as compared to the control plants, was preferentially used for thick root growth. This result shows that photosynthesis in young spruce forests can deposit excess atmospheric CO₂ in the soil horizon in the form of thick root phytomass. __________ Translated from Fiziologiya Rastenii, Vol. 52, No. 5, 2005, pp. 741–746. Original Russian Text Copyright ? 2005 by Mao, Y.-J. Wang, Zhu, X.-W. Wang, Sun, Zhou, Voronin.     

Comparison of whole-blood glutathione peroxidase activity,levels of serum selenium,and lipid peroxidation in subjects from the fishing and rural communities of "Rabo de Peixe" village,San Miguel Island,the Azores' Archipelago,Portugal

The activity of glutathione peroxidase (GSH-Px), serum selenium (Se), and thiobarbituric acid reactive substances (TBARS) were measured in the whole blood of 148 healthy adults aged 20–60 yr from the fishing and rural communities of “Rabo de Peixe,” The Azores, Portugal. The subjects did not live in the same household and had different socioeconomic profiles and dietary habits. The serum lipid profile and selected life habits were also considered in this study. No significant differences in the activity of GSH-Px were found in the interpopulation or intrapopulation analyses, classified by age or lipid profile. An age-dependent GSH-Px increase was noted in the younger male (M) subgroups (20–39 yr). The Se levels were higher in fishers (f) of both genders (M, F) than in subjects living in the rural (r) environment: 110±25 μg/L (f, M), 89±20 μg/L (f, F), 88±22 μg/L (r, M) and 80±17 μg/L (r, F). In the fishers, but not in the rural population, Se was higher in the males, but it did not show significant variation with age. The levels of TBARS were lower in the f than in the r male group. The Se level was lower and TBARS higher in the hyperlipemic women in the f group, compared to the corresponding controls. Our results suggest that the fishers (mainly men) show a better antioxidant status than that of their rural counterparts, due to differences in dietary habits between the study populations and between genders.     

Latitudinal changes in species diversity of permafrost wetland plant communities in Great Xing’an Mountain valleys of Northeast China

Studying the changes of species diversity in plant communities along latitude gradients is important to discover the correlation between biodiversity and environmental factors. Along the main ridges of the Great Xing’an Mountains, 12 natural permafrost wetlands in the valleys were investigated from north to south. Latitudinal changes in species diversity were analyzed with regressive analysis. About 150 plant species were recorded and were found to be in the 12 permafrost wetland plant communities. Most plants belong to the Compositae or Gramineae. The number of family, genus and species increased significantly in the herb layer with decreasing latitude (P < 0.01), but decreased significantly in the shrub layer (P < 0.01). Species composition and the orders of dominant species in the plant communities by importance value changed along latitude. Latitudinal changes of α-diversity in permafrost wetland plant communities were different in the herb and shrub layers. With decreasing latitude, species richness and species diversity increased in the herb layer; but decreased in the shrub layer. The opposite patterns were found for species dominance. Species evenness in the shrub layer decreased with decreasing latitude. ?-diversity in the herb and shrub layers decreased first, and then increased, and finally decreased with increasing latitude. Species composition in the herb layer was similar among the plots at higher latitudes.     

Selenium contentrations in human renal cortex, liver, and hair in Northern Poland

The aim of this study was to (1) determine the selenium concentration in the renal cortex, liver, and hair in 64 residents from northern Poland (Gdańsk region) aged 17–81 yr, who died suddenly, and (2) assess whether a correlation between the selenium concentration in hair and in the renal cortex and liver occurs. Selenium was determined by atomic absorption spectrometry using the hydride generation method. The mean selenium concentration in the renal cortex, liver, and hair in the investigated persons was 0.791±0.191 μg/g (wet weight), 0.289±0.084 μg/g (wet weight), and 0.443±0.128 μg/g, respectively. No age-dependent differences in selenium level in the investigated tissues was found. Also, no correlation between the selenium concentrations in hair and in renal cortex and liver was assessed.     

Modulation of spiking of neurons of the cat anterior hypothalamus induced by experimental shifts in the osmolarity of the blood plasma

We examined changes in the impulse activity (IA) generated by neurons of the anterior hypothalamus (including the preoptic region) resulting from infusions of hyper-and hypotonic NaCl solutions (3.0 and 0.2%, respectively; hyper-and hypoosmotic stimulations, respectively); the infused volumes did not exceed 200 μl. The effects of hyper-and hypoosmotic stimulations were studied in detail in 83 and 88 neurons, respectively. In 31.2% (26 cells) and 29.6% (26 cells) of the neurons of the above groups, these stimulations evoked changes in the IA frequency greater than +40 or −40% of the mean background IA frequency. In approximately 50% of the responding neurons in each group, such shifts in the IA frequency were observed in the course of infusions of test solutions (5 sec long) and within the subsequent 5 min after termination of the infusion. In another 50% of the neurons, changes in the IA frequency occurred within the afterperiod (30 sec long); these shifts could develop exclusively within the latter interval, or these changes accompanied an initial early reaction. In general, activating responses dominated (they were observed in 65% of the cases where test stimulations of both modalities were used). The possible aspects of the involvement of neurons of the anterior hypothalamus in the control of the water/salt balance in the organism are discussed. Neirofiziologiya/Neurophysiology, Vol. 38, No. 1, pp. 40–45, January–February, 2006.     

The effects of oligomycin on content of adenylates in mesophyll protoplasts,chloroplasts and mitochondria from Pb<Superscript>2+</Superscript> treated pea and barley leaves

The effects of oligomycin on photosynthesis and respiration in relation to ATP production in chloroplasts and mitochondria were investigated in protoplasts isolated from the detached pea (Pisum sativum L cv. Iłowiecki.) and barley (Hordeum vulgare L. cv. Gunilla) leaves treated 5 mM Pb(NO₃)₂. The oligomycin (OM), an inhibitor of oxidative phosphorylation at 0.1 μM concentration caused the inhibition of photosynthesis rate in the protoplasts from both the control and the Pb-treated pea leaves. The respiration rate and ATP/ADP ratio in the protoplasts and the activity of ATPase in mitochondria, were also diminished in the control protoplasts. These effects were not observed in the protoplasts and mitochondria isolated from the Pb-treated leaves. Oligomycin, an inhibitor of photophosphorylation at 10 μM concentration decreased ATPase activity in chloroplasts from both the control and the Pb- treated leaves. Using the method of rapid fractionation of barley protoplasts it was shown that the ATP/ADP ratio in the mitochondria from Pb-treated leaves was largely suppressed (from 1.8 to 0.4) by OM under nonphotorespiratory conditions (high CO₂), whereas under photorespiratory conditions (low CO₂) this ratio was high (5.3) and under OM decreased less (to 3.1). Our results indicate that oligomycin, in organelle isolated from Pb-treated leaves, had no inhibitory effect on the mitochondrial ATPase, whereas it inhibited chloroplasts ATPase. We suggest that Pb ions affected the catalytic cycle and/or conformational changes of ATPase in pea chloroplasts differently than in mitochondria. The differences in Pb responses may reflect fine mechanisms for the regulation of ATP production in the plant cells under stress conditions.