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1.
Kravchenko  K. L.  Prikop  M. V.  Bazhenov  A. A. 《Biophysics》2017,62(4):671-674

Analysis of the motions of Drosophila melanogaster laboratory populations and their relationship to the heliogeophysical parameters (the radio-wave flux at the wavelength of 10.7 cm (F10.7), Wolf numbers (W), the planetary K p-index, an indicator of geomagnetic activity) was carried out. A significant correlation between the changes in the characteristics of solar activity (F10.7, W) and the dynamics of the motions of Drosophila was detected. The association strongly depends on the sexual structure of the Drosophila populations, which follows from the difference in the distributions of this association.

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2.
The relationship between the time series of the dynamics of the numbers of experimental populations of Drosophila melanogaster at the preimaginal stage and three heliogeophysical indices: Wolf numbers, the intensity of the 10.7-cm radio flux, and the Kp-index of geomagnetic activity was analyzed. Statistically significant data were obtained indicating that the dynamics of the number of the populations is related to the heliogeophysical factors, and this relationship depends on the phase of the 11-year cycle of solar activity. It was shown that the fertility of females and the survival of eggs is stimulated by factors associated with solar activity.  相似文献   

3.
A correlation between variations in the medical parameters and the heliogeophysical indices describing physical processes during solar storms was established. It was proposed that one of the reasons for the biotropic effects observed is rheological shifts of human blood during enhancement of solar activity. The influence of heliogeophysical disturbances on the rheological properties of blood was investigated.  相似文献   

4.
The correlation between the parameters of biologically active points and the dynamics of solar activity was studied. Statistically significant correlations between electroconductivity of biologically active points and solar activity indices (sunspot number, Ap-index, solar radiowave flux) were revealed. The spectral analysis of the temporal organization of biologically active points revealed a set of periods present in the dynamics of solar activity. It was concluded that bioelectric system of the human organism is a complicated multilevel time-structure, which effectively reacts to changes in heliogeophysical dynamics. The bioelectric system of biologically active points is considered to be one of general information channels of electromagnetic nature, which realize the connection of organism with environment.  相似文献   

5.
Intertidal macroalgae are constantly subjected to high variations in the quality and quantity of incident irradiance that can eventually generate detrimental effect on the photosynthetic apparatus. The success of these organisms to colonize the stressful coastal habitat is mainly associated with the complexity of their morphological structures and the efficiency of the anti-stress mechanisms to minimize the physiological stress. Lessonia spicata (Phaeophyceae), a brown macroalga, that inhabits the intertidal zone in central–southern Chile was studied in regard to their physiological (quantum yield, electron transport rate, pigments) and biochemical (phlorotannins content, antioxidant metabolism, oxidative stress) responses during a daily light cycle under natural solar radiation. Major findings were that F v/F m, photosynthetic parameters (ETRmax, alpha, E k) and pigments in L. spicata showed an inverse relationship to the diurnal changes in solar radiation. Phlorotannins levels and antioxidant activity showed their highest values in treatment that included UV radiation. There was an increase in SOD and APX in relation at light stress, with a peak in activity between 5.2 and 10.1 W m?2 of biologically effective dose. The increase in peroxidative damage was proportional to light dose. These results indicated that different light doses can trigger a series of complementary mechanisms of acclimation in L. spicata based on: (i) down-regulation of photochemistry activity and decrease in concentration of photosynthetic pigments; (ii) induction of phenolic compounds with specific UV-screening functions; and (iii) reactive oxygen species (ROS) scavenging activity via complementary repair of the oxidative damage through increased activity of antioxidant enzymes and potentially increased amounts of phenolic compounds.  相似文献   

6.
Using mass-spectrometric measurements of 18O exchange from 13C18O2 intracellular carbonic anhydrase (CA) activity was investigated in the unicellular green algae Dunaliella tertiolecta and Chlamydomonas reinhardtii which were either grown on air enriched with 5% CO2 (high-Ci cells) or on air (low-Ci cells). In D. tertiolecta high- and low-Ci cells had detectable levels of internal CA activity when measured under in-vivo conditions and this activity could be split up into three distinct forms. One CA was not associated with the chloroplasts, while two isozymes were found to be located within the plastids. The activities of all intracellular CAs were always about twofold higher in low than in high-Ci cells of D. tertiolecta and the chloroplastic enzymes were completely induced within 4 h of adaptation to air. One of the chloroplastic CAs was found to be soluble the other was insoluble. In addition to the physical differences, MgSO4 in vitro caused a more than twofold stimulation of the soluble activity while the insoluble form of CA remained rather unaffected. In C. reinhardtii, MgSO4 increased the soluble CA activity by 346% and the concentration of MgSO4 required for half-maximum stimulation was between 10 and 15 mM. Again, the insoluble CA activity was not affected by MgSO4. Furthermore, the soluble isoenzyme was considerably more sensitive to ethoxyzolamide, a potent inhibitor of CA, than the insoluble enzyme. The concentration of inhibitor causing 50% inhibition of soluble CA activity was 110 and 85 μM ethoxyzolamide for D. tertiolecta and C. reinhardtii, respectively. From these data we conclude that the two chloroplast-associated CAs are distinct enzymes.  相似文献   

7.
The relationship between O2-based gross photosynthesis (GP) and in vivo chlorophyll fluorescence of Photosystem II-based electron transport rate (ETR) as well as the relationship between effective quantum yield of fluorescence (ΦPSII) and quantum yield of oxygen evolution (ΦO_2) were examined in the green algae Ulva rotundata and Ulva olivascens and the red alga Porphyra leucosticta collected from the field and incubated for 3 days at 100 μmol m−2 s−1 in nutrient enriched seawater. Maximal GP was twice as high in Ulva species than that measured in P. leucosticta. In all species ETR was saturated at much higher irradiance than GP. The initial slope of ETR versus absorbed irradiance was higher than that of GP versus absorbed irradiance. Only under absorbed irradiances below saturation or at values of GP <2 μmol O2 m−2 s−1 a linear relationship was observed. In the linear phase, calculated O2 evolved /ETR molar ratios were closed to the theoretical value of 0.25 in Ulva species. In P. leucosticta, the estimated GP was associated to the estimated ETR only at high irradiances. ETR was determined under white light, red light emitting by diodes and solar radiation. In Ulva species the maximal ETR was reached under red light and solar radiation whereas in P. leucosticta the maximal ETR was reached under white light and minimal under red light. These results are in agreement with the known action spectra for photosynthesis in these species. In the case of P. leucosticta, GP and ETR were additionally determined under saturating irradiance in algae pre-incubated for one week under white light at different irradiances and at white light (100 μmol m−2 s−1) enriched with far-red light. GP and growth rate increased at a growth irradiance of 500 μmol m−2 s−1 becoming photoinhibited at higher irradiances, while ETR increased when algae were exposed to the highest growth irradiance applied (2000 μmol m−2 s−1). The calculated O2 evolved /ETR molar ratios were close to the theoretical value of 0.25 when algae were pre-incubated under 500–1000 μmol m−2 s−1. The enrichment by FR light provoked a decrease in both GP and ETR and an increase of nonphotochemical quenching although the irradiance of PAR was maintained at a constant level. In addition to C assimilation, other electron sinks, such as nitrogen assimilation, affected the GP–ETR relationship. The slopes of GP versus ETR or ΦPSII versus ΦO_2 were lower in the algae with the highest N assimilation capacity, estimated as nitrate reductase activity and internal nitrogen contents, i.e., Ulva rotundata and Porphyra leucosticta, than that observed in U. olivascens. The possible mechanisms to explain this discrepancy between GP and ETR are discussed. This revised version was published online in June 2006 with corrections to the Cover Date.  相似文献   

8.
Correlations between the parameters of life-span (LS) distribution of Drosophila melanogaster, including mean LS (MLS) and the time of 10 and 90% population mortality, and some geophysical parameters that are usually beyond the control of researchers dealing with laboratory cultures, including atmospheric pressure, solar activity indices (Wolfs sunspot numbers and 2,800-MHz radio flux), and geomagnetic activity (planetary index, Kp), were studied. Geophysical data were obtained from free-access official web sites of the National Oceanic & Atmospheric Administration of the US Department of Commerce and the Institute of Terrestrial Magnetism and Radiowave Propagation of the Russian Academy of Sciences. The geophysical parameters were calculated only for the period corresponding to 10 days of preimaginal development of the flies from egg to imago. Canonical correlation analysis, calculation of the non-parametric Spearman rank-order correlation coefficients, and graphical data analysis were used. Highly significant correlations between parameters of LS distribution in males and females and environmental factors, such as the atmospheric pressure on the 4th and 5th day of development and geomagnetic activity indices (Kp) on the 6th and 10th day of development were found, with correlation coefficients varying from 0.31 to 0.37 (P<0.02). Assuming a causal relationship between geophysical factors and LS, it may be hypothesized that energetically weak environmental factors determine the formation of LS oscillatory dynamics in laboratory populations. The possible mechanisms underlying the contribution of these environmental factors to the LS variation in successive generations are discussed.  相似文献   

9.
L-Lactate cytochrome c oxidoreductase (flavocytochrome b 2, FC b 2) from the thermotolerant methylotrophic yeast Hansenula polymorpha (Pichia angusta) is, unlike the enzyme form baker’s yeast, a thermostable enzyme potentially important for bioanalytical technologies for highly selective assays of L-lactate in biological fluids and foods. This paper describes the construction of flavocytochrome b 2 producers with over-expression of the H. polymorpha CYB2 gene, encoding FC b 2. The HpCYB2 gene under the control of the strong H. polymorpha alcohol oxidase promoter in a plasmid for multicopy integration was transformed into the recipient strain H. polymorpha C-105 (grc1 catX), impaired in glucose repression and devoid of catalase activity. A method was developed for preliminary screening of the transformants with increased FC b 2 activity in permeabilized yeast cells. The optimal cultivation conditions providing for the maximal yield of the target enzyme were found. The constructed strain is a promising FC b 2 producer characterized by a sixfold increased (to 3 μmol min?1 mg?1 protein in cell-free extract) activity of the enzyme.  相似文献   

10.
Rozanov MI  Prokudina VS 《Biofizika》2002,47(1):135-138
Fluctuations in the width of annual tree rings in the time interval from the eighth century till the present time were analyzed on the basis of dendroclimatic scales. Periods of extremely high and low growth of trees were distinguished, and their correlations with heliogeophysical factors were studied. The major climatic parameters determining the growth of trees are warmth and moisture; a small gain is observed in cold and droughty periods. No correlations between the width of tree rings and the minima and maxima of solar activity cycles were observed with the method used.  相似文献   

11.
Paulo Vale 《Biophysics》2014,59(3):464-474
Accumulation of paralytic shellfish poisoning toxins (PSTs) in bivalves attributed to Gymnodinium catenatum blooms at the NW Portuguese coast was previously associated with periods of low solar activity (measured by the radio flux R), or low geomagnetic A a index. It was also observed that reduction of R preceded the occurrence of toxin accumulation, while the A a index increase could be related to its absence during periods of low activity. For modeling toxin accumulation, the monthly decrease in R was studied along the decade 2003–2012. A match that helped explaining the highly toxic years of 2007 and 2008 was obtained by plotting the formula: ΔR = (R n ? 1 ? R n )/(R n ? 65)2, where 65 represented the lowest radio activity known to date. The complex denominator was required to take into account the sunspot cycle. A 1–2-month lag was observed between maximal relative decline and maximal PST accumulation. PSTs in bivalves from the Portuguese south coast were related with natural electromagnetic cycles for the first time, and were not statistically associated with low R. A statistically significant association with low A a index also was not achieved, due to the low number of occurrences, although the 25–75 percentile was restricted to low A a indexes in a similar way to that found for the NW coast. PST accumulation outside solar minima could be triggered by a steep decline in the A a index (ΔA), but no lag was observed in this case. While the ΔR amplitude helped explaining the highly toxic years of 2007 and 2008 at the NW coast, the amplitude of ΔA was not related to the severity of the accumulation. Another kind of local electromagnetic signaling was investigated resorting to the occurrence of seismologic phenomena, because these events can trigger electric activities. No statistical association was found between seism number or magnitude and PSTs at the south coast, located near the boundary between the African and Eurasian plates, and marked by moderate seismicity.  相似文献   

12.
On the basis of a two-component (two-fluid) hydrodynamic model, it is shown that the probable phenomenon of solar core rotation with a velocity higher than the average velocity of global rotation of the Sun, discovered by the SOHO mission, can be related to fast solid-body rotation of the light hydrogen component of the solar plasma, which is caused by thermonuclear fusion of hydrogen into helium inside the hot dense solar core. Thermonuclear fusion of four protons into a helium nucleus (α-particle) creates a large free specific volume per unit particle due to the large difference between the densities of the solar plasma and nuclear matter. As a result, an efficient volumetric sink of one of the components of the solar substance—hydrogen—forms inside the solar core. Therefore, a steady-state radial proton flux converging to the center should exist inside the Sun, which maintains a constant concentration of hydrogen as it burns out in the solar core. It is demonstrated that such a converging flux of hydrogen plasma with the radial velocity v r (r) = ?βr creates a convective, v r ?v φ/?r, and a local Coriolis, v r v φ/r,φ nonlinear hydrodynamic forces in the solar plasma, rotating with the azimuthal velocity v φ. In the absence of dissipation, these forces should cause an exponential growth of the solid-body rotation velocity of the hydrogen component inside the solar core. However, friction between the hydrogen and helium components of the solar plasma due to Coulomb collisions of protons with α-particles results in a steady-state regime of rotation of the hydrogen component in the solar core with an angular velocity substantially exceeding the global rotational velocity of the Sun. It is suggested that the observed differential (liquid-like) rotation of the visible surface of the Sun (photosphere) with the maximum angular velocity at the equator is caused by sold-body rotation of the solar plasma in the radiation zone and strong turbulence in the tachocline layer, where the turbulent viscosity reaches its maximum value at the equator. There, the tachocline layer exerts the most efficient drag on the less dense outer layers of the solar plasma, which are slowed down due to the interaction with the ambient space plasma (solar wind).  相似文献   

13.
吴芳芳  郑有飞  吴荣军  王锦旗  李萍 《生态学报》2015,35(12):3949-3958
采用开顶箱(OTC)法和遮光网技术,设置100 n L/L臭氧熏气与3个辐射减弱梯度结合,模拟臭氧浓度升高和太阳辐射减弱的复合大气背景。用BIOLOG生态测试板,采用孔平均颜色变化率法(AWCD)测定冬小麦根际土壤微生物利用不同碳源的能力,计算微生物群落多样性指数,对不同碳源的利用率进行了主成分分析。两年试验结果显示,臭氧熏气与太阳辐射减弱复合作用,降低了土壤微生物对碳源的利用速度和利用总量;除了聚合物以外其它碳源利用率显著降低;对土壤微生物多样性没有直接的影响;对碳源降解的抑制效应大于增强的O3与减弱的太阳辐射两因素各自的单独作用。太阳辐射减弱20%,一定程度上增加了对聚合物类的分解。O3熏气条件下太阳辐射减弱,糖类、胺类代谢变异度较高,受环境影响较大。  相似文献   

14.
The T7 antirestriction protein Ocr, encoded by 0.3 (ocr), specifically inhibits ATP-dependent type I restriction-modification systems. T7 0.3 (ocr) was cloned in pUC18. Ocr inhibited both restriction and modification activities of the type I restriction-modification system (EcoKI) in Escherichia coli K12. The Ocr F53D A57E mutant was obtained and proved to inhibit only restriction activity of EcoKI. The 0.3 (ocr) and Photorhabdus luminescens luxCDABE genes were cloned in pZ-series vectors with the P ltetO-1 promoter, strongly controlled by the TetR repressor. The bioluminescence intensity and luciferase content varied up to 5000-fold in E. coli K12 MG1655Z1 tetR+ (pZE21-luxCDABE) cells, depending on the environmental concentration of the inductor anhydrotetracycline. The antirestriction activity of Ocr and Ocr F53D A57E was studied as a function of their concentration in the cell. The dissociation constant K d, characterizing the binding with EcoKI, differed 1000-fold between Ocr and Ocr F53D A57E (10?10 M versus 10?7 M).  相似文献   

15.
Escherichia coli grown under anaerobic conditions in acidic medium (pH 5.5) upon hyperosmotic stress accumulates potassium ions mainly through the Kup system, the functioning of which is associated with proton efflux decrease. It was shown that H+ secretion but not glucose-induced K+ uptake was inhibited by N,N′-dicyclohexylcarbodiimide (DCC). The inhibitory effect of DCC on the H+ efflux was stronger in the trkA mutant with defective potassium transport. The K+ and H+ fluxes depended on the extent of hyperosmotic stress in the absence or presence of DCC. The decrease in external oxidation/reduction potential and H2 liberation insensitive to DCC were recorded. It was found that the atpD mutant with nonfunctional F0F1-ATPase produced a substantial amount of H2, while in the hyc mutant (but not the hyf mutant defective in hydrogenases 3 (Hyd-3) and 4 (Hyd-4)) the H2 production was significantly suppressed. At the same time, the rate of K+ uptake was markedly lower in hyfR and hyfB-R but not in hycE or hyfA-B mutants; H+ transport was lowered and sensitive to DCC in hyf but not in hyc mutants. The results point to the relationship of K+ uptake with the Hyd-4 activity. Novel options of the expression of some hyf genes in E. coli grown at pH 5.5 are proposed. It is possible that the hyfB-R genes expressed under acidic conditions or their gene products interact with the gene coding for the Kup protein or directly with the Kup system.  相似文献   

16.
Several strains of Rhizobium resistant to spectinomycin also had nitrogenase activity (C2H2 reduction and H2 production) in static culture under 95% Ar/1%O2/4%C2H2. This relationship between nitrogenase activity and spectinomycin resistance was observed in both fast-growing (R. trifolii and R. leguminosarum) and slow-growing (R. japonicum) rhizobia. The effect of different media and various carbon sources on nitrogenase activity was investigated in more detail in R. trifolii strain TlSp. This communication demonstrates that fast-growing rhizobia can have nitrogenase activity in the absence of any plant component.  相似文献   

17.
Scattering efficiencies of Ag–Cu, Ag–Au, and Au–Cu alloy nanoparticles are studied based on Mie theory for their possible applications in solar cells. The effect of size (radius), surrounding medium, and alloy composition on the scattering efficiency at the localized surface plasmon resonance (LSPR) wavelengths has been reported. In the alloy nanoparticles of Ag1?x Cu x , Au1?x Cu x and Ag1?x Au x ; the scattering efficiency gets red-shifted with increase in x. Moreover, the scattering efficiency enhancement can be tuned and controlled with both the alloy composition and the surrounding medium refractive index. A linear relationship which is in good agreement to the experimental observations between the scattering efficiency and metal composition in the alloys are found. The effect of nanoparticle size and LSPR wavelength (scattering peak position) on the full width half maxima and scattering efficiency has also been studied. Comparison of Au–Ag, Au–Cu, and Ag–Cu alloy nanoparticles with 50-nm radii shows the optical response of Ag–Cu alloy nanoparticle with wide bandwidth in the visible region of the electromagnetic spectrum making them suitable for plasmonic solar cells. Further, the comparison of Ag–Cu alloy and core@shell nanoparticles of similar size and surrounding medium shows that Cu@Ag nanoparticle exhibits high scattering efficiency with nearly the same bandwidth.  相似文献   

18.
Leishmaniasis is one of the major infectious diseases affecting the poorest regions of the world. The present study evaluated the antileishmanial activity of a guaianolide purified from the hydroalcoholic extract of aerial parts of Tanacetum parthenium (L.) Schultz Bip. The isolated compound showed activity against the promastigote form of Leishmania amazonensis, with 50% inhibition (IC50) of cell growth at a concentration of 2.6 μg/ml. For the intracellular amastigote form, this guaianolide reduced by 10% the survival index of parasites in macrophages when it was used at 20.0 μg/ml. The selective index (SI) ratio (CC50 for J774G8 cells/IC50 for protozoans) was 385, showing that it is more selective against the parasite than mammalian cells. Morphological alterations of protozoans treated with IC50 included changes in size, shape, and structure (more than one nucleus and flagellum) under both light and scanning electron microscopies.  相似文献   

19.
The interaction of secreted aspartic proteinases from C. albicans (C. albicans SAP) with ZnCl2 and MnCl2 has been studied. Logarithms of stability constant from the data of electronic spectroscopy were calculated for the complexes of SAP with Zn (II) (SAP-ZnII, logβ = 4.73 ± 0.20) and with Mn(II) (SAP-MnII, logβ = 7.02 ± 0.20). The composition and maximum accumulation of complexes in solution were calculated. The optimal conditions of hydrolysis of the substrate, HAS (human serum albumin) in the presence of C. albicans SAP-MnII and SAP-ZnII proteinases were determined. These were: [HSA] = 1 mg/ml, [SAP] = 2.33 μM, pH = 4.5, incubation time of 25 min. The activity of C. albicans SAP in the presence of different concentrations of ZnCl2 and MnCl2 was evaluated under optimal conditions of enzymatic hydrolysis. For the first time the activating action of 0.5 μM ZnCl2 on catalytic activity of C. albicans SAP proteinase has been demonstrated. The maximal rate of enzymatic reaction (V max), the Michaelis constant (K m ) and constants of effects in the presence and in the absence of the effector, ZnCl2, were calculated. The albuminase activity of C. albicans pathogenic strains of different localization was evaluated in the presence and the absence of the effector of ZnCl2.  相似文献   

20.
The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT50 > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT50 < 120 min irradiation. The QSUN Xenon Test Chamber XE3 is often used by the pharmaceutical and automotive industry to test light stability and weathering, respectively, but it was never used to evaluate fungal tolerance to full-spectrum solar radiation before. We conclude that the equipment provided an excellent tool for testing realistic tolerances of fungi to full-spectrum solar radiation of microbial agents for insect biological control in agriculture.  相似文献   

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