物理最新文献

{"title":"Assessment of Antenna Heterogeneity and the Activity of the Oxygen-Evolving Complex of Photosystem II Using Mathematical Methods","authors":"N. S. Degtereva,&nbsp;T. Yu. Plyusnina,&nbsp;S. S. Khrushchev,&nbsp;R. N. Chervitsov,&nbsp;E. N. Voronova,&nbsp;O. V. Yakovleva,&nbsp;T. K. Antal,&nbsp;G. Yu. Riznichenko,&nbsp;A. B. Rubin","doi":"10.1134/S0006350924700490","DOIUrl":"10.1134/S0006350924700490","url":null,"abstract":"<div><p>Photosystem II is one of the main pigment–protein complexes of photosynthesis, which is highly sensitive to adverse environmental factors. The heterogeneity of photosystem II properties is necessary for the resistance of autotrophic organisms to stress factors. The assessment of photosystem II heterogeneity can be used in environmental monitoring for the rapid detection of environmental pollution. A comprehensive approach to the assessment of photosystem II heterogeneity is proposed; it is based on a mathematical analysis of the shape of the chlorophyll <i>a</i> fluorescence induction curve of samples treated with 3-(3,4-dichlorophenyl)-1,1-dimethyl urea using a mathematical model and JIP test parameters. Fluorescence induction curves obtained for treated samples of <i>Chlorella</i>, <i>Scenedesmus</i>, <i>Ankistrodesmus</i>, <i>Pleurochloris</i>, and <i>Stichococcus</i> cell cultures were analyzed that grew in light with an intensity of 8 and 16 W/m^–2. For all cases, the ratio of reaction centers with different antenna sizes (alpha and beta centers) was estimated and the proportion of active and inactive oxygen-evolving complexes was determined.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"408 - 417"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859733","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The structure of the (f_0(980)) from system size dependent hadronic resonance ratios in p + p, p + Pb, and Pb + Pb collisions at the LHC","authors":"Tom Reichert,&nbsp;Jan Steinheimer,&nbsp;Volodymyr Vovchenko,&nbsp;Christoph Herold,&nbsp;Ayut Limphirat,&nbsp;Marcus Bleicher","doi":"10.1140/epjc/s10052-024-13690-w","DOIUrl":"10.1140/epjc/s10052-024-13690-w","url":null,"abstract":"<div><p>It is shown that the hadronic phase in ultra-relativistic heavy ion collisions can be used to understand the properties of the <span>(f_0(980))</span> resonance. In particular it is shown that the centrality dependence of the <span>(f_0(980)/pi )</span> and <span>(f_0(980)/phi )</span> ratios depends strongly on the <span>(f_0(980)rightarrow {overline{K}}+K)</span> branching ratio and whether the <span>(f_0(980))</span> is produced as a <span>(left| {overline{q}}q rightrangle )</span> or <span>(left| {overline{s}}s rightrangle )</span> state. These conclusions are drawn from calculations within the partial chemical equilibrium of the HRG model within Thermal-FIST as well as with the fully non-equilibrium hybrid-transport approach UrQMD. Our findings show how the hadronic phase in heavy ion collisions can be used for studies of exotic hadron properties otherwise possible only in dedicated experiments such as PANDA.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13690-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Bioluminescent Test System Based on Recombinant L. mingrelica Firefly Luciferase as a Means of Investigating the Efficacy of the Gentamicin Effect on Live E. coli Cells","authors":"G. Yu. Lomakina,&nbsp;S. S. Kaminskaya,&nbsp;N. N. Ugarova","doi":"10.1134/S0006350924700556","DOIUrl":"10.1134/S0006350924700556","url":null,"abstract":"<div><p>The possibilities of using a test system based on live <i>E. coli</i> BL-21 (DE3) Codon Plus cells expressing pH-resistant <i>Luciola mingrelica</i> firefly luciferase to study the kinetics of the effect of aminoglycosides (using the example of gentamicin) on the content of ATP and luciferase inside and outside the cells were demonstrated. It has been shown that after 3 h of incubation of bacteria with an antibiotic it was possible to assess changes in cell viability and the effectiveness of the antibiotic, as well as to predict the formation of persisters. The method is promising for conducting rapid primary high-performance screening of antibacterial agents and drug forms to assess their effectiveness and the mechanism of action.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"477 - 484"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of selected physical parameters on the gamma-ray-induced EPR signal of glycine dosimeter","authors":"E. Aboelezz,&nbsp;M. A. Sharaf","doi":"10.1140/epjp/s13360-024-05876-8","DOIUrl":"10.1140/epjp/s13360-024-05876-8","url":null,"abstract":"<div><p>Electron paramagnetic resonance (EPR) dosimetric characteristics of glycine irradiated with a broad range of gamma doses, ranging from 0.1 Gy up to 100 kGy, were examined. Further physical parameters were investigated, such as irradiation temperature, dose fractionation, fading for different isothermal annealing temperatures, and UV exposure. The gamma dose response of glycine represents ~ 36% of that of alanine at a gamma dose of 5 kGy, and this ratio decreases as the gamma dose increases. The calculated detection limit is about 130 mGy. There is no significant variation in the EPR intensity of exposed glycine due to the change in the intermediate intervals between the two fractions. The optimum annealing temperature and duration time overcoming the fading impact for immediate readout of glycine after irradiation were found to be 110 °C for 15 min. UVC induces a broad peak in the unirradiated glycine sample at the same position that overlaps with the dosimetric peak of gamma rays. Keeping the glycine dosimeter in the dark is recommended to prevent the UV effect.</p></div>","PeriodicalId":792,"journal":{"name":"The European Physical Journal Plus","volume":"139 12","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjp/s13360-024-05876-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analyzing the speed of sound in neutron star with machine learning","authors":"Sagnik Chatterjee,&nbsp;Harsha Sudhakaran,&nbsp;Ritam Mallick","doi":"10.1140/epjc/s10052-024-13668-8","DOIUrl":"10.1140/epjc/s10052-024-13668-8","url":null,"abstract":"<div><p>Matter properties at the intermediate densities are still unknown to us. In this work, we use a neural network approach to study matter at intermediate densities to analyze the variation of the speed of sound and the measure of trace anomaly considering astrophysical constraints of mass–radius measurement of 18 neutron stars. Our numerical results show that there is a sharp rise in the speed of sound just beyond the saturation energy density. It attains a peak around 3–4 times the saturation energy density and, after that, decreases. This hints towards the appearance of new degrees of freedom and smooth transition from hadronic matter in massive stars. The trace anomaly is maximum at low density (surface of the stars) and decreases as we reach high density. It approaches zero and can even be slightly negative at the centre of massive stars. It has a negative trough beyond the maximal central densities of neutron stars. The change in sign of the trace anomaly hints towards a near-conformal matter at the centre of neutron stars, which may not necessarily be conformal quark matter.</p></div>","PeriodicalId":788,"journal":{"name":"The European Physical Journal C","volume":"84 12","pages":""},"PeriodicalIF":4.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1140/epjc/s10052-024-13668-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Viscous Media on the Quantum Yield of Bioluminescence in a Reaction Catalyzed by Bacterial Luciferase","authors":"A. E. Lisitsa,&nbsp;L. A. Sukovatyi,&nbsp;V. A. Kratasyuk,&nbsp;E. V. Nemtseva","doi":"10.1134/S0006350924700465","DOIUrl":"10.1134/S0006350924700465","url":null,"abstract":"<p>Based on the data on the transient kinetics of the bioluminescent reaction catalyzed by <i>P. leiognathi</i> luciferase in media with polyols and sugars, the relative quantum yield of bioluminescence in this reaction per substrate molecule was determined using mathematical modeling. It was obtained that in some media the relative quantum yield per aldehyde molecule increases compared to the value in the buffer: by 18 and 33% in the presence of glycerol and sucrose, respectively. Molecular dynamics methods were used to analyze the side-chain conformation of αHis44 – a residue of bacterial luciferases that is known to play an essential role in catalysis. It was found that in the presence of all cosolvents an increased frequency of occurrence of the αHis44 conformation, which is optimal for catalysis, is observed. This effect can contribute to the observed increase in the quantum yield of bioluminescence of the studied reaction in viscous media.</p>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"380 - 389"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photochemical Energy Conversion of Far-Red Light in Photosystem I Reaction Centers from Cyanobacterium Acaryochloris marina","authors":"A. A. Petrova,&nbsp;A. P. Casazza,&nbsp;S. Santabarbara,&nbsp;D. A. Cherepanov","doi":"10.1134/S0006350924700507","DOIUrl":"10.1134/S0006350924700507","url":null,"abstract":"<div><p>The conversion of light energy in the near-infrared spectral range by photosynthetic pigment–protein complexes has been intensively studied in recent years in connection with the discovery of cyanobacteria, in the photosynthetic apparatus of which chlorophylls <i>f</i> and <i>d</i> absorbing long-wavelength light are present. <i>Acaryochloris marina</i> occupies a special place among such cyanobacteria. Its photosystem I contains mainly chlorophyll <i>d</i>; it is a part of a special P₇₄₀ pair, the absorption spectrum of which is shifted to the red region by 40 nm. This causes a decrease in the energy of the excited state of P₇₄₀ by ~0.1 eV compared with photosystem I containing chlorophyll <i>a</i>. Complexes of photosystem I from <i>A. marina</i> also have the following peculiarities: four chlorophyll <i>a</i> molecules of the reaction center are replaced by chlorophyll <i>d</i>, and the third pair of chlorophyll <i>a</i> molecules involved in electron transfer are replaced by pheophytin <i>a</i>. The presence of spectrally different cofactors (chlorophyll <i>d</i> and pheophytin <i>a</i>) made it possible to reliably establish the intermediates of primary charge separation reactions in this photosystem I. In this review, we considered the latest results of studies of photochemical energy conversion in the reaction centers of photosystem I of <i>A. marina</i> and possible mechanisms for compensating energy losses of the use of low-energy far-red light for photosynthesis.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"418 - 433"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effects of Caffeic Acid, Hispidin and a Discovered Activating Component on Luminescence of Mycelium and a Luminescent System of the Basidiomycete Neonothopanus nambi","authors":"N. O. Ronzhin,&nbsp;E. D. Posokhina,&nbsp;V. M. Le,&nbsp;O. A. Mogilnaya,&nbsp;Yu. V. Zakharova,&nbsp;A. S. Sukhikh,&nbsp;V. S. Bondar","doi":"10.1134/S0006350924700544","DOIUrl":"10.1134/S0006350924700544","url":null,"abstract":"<div><p>It was found in vivo that the addition of caffeic acid and a low-molecular-weight bioluminescence activator that we have discovered to the mycelium of the luminous fungus <i>Neonothopanus nambi</i> led to a rapid and significant (by an order of magnitude and more) increase in the intensity of its light emission. It is proposed that the observed effect of activation of the fungus glow may be mediated by the oxidation of added substances by enzymes of the ligninolytic complex of basidiomycetes (in particular, peroxidases) with the emission of visible light quanta. Parallel <i>in vivo</i> experiments have shown that the addition of hispidin (a precursor of luciferin in luminous higher fungi) did not affect the intensity of light emission of the mycelium. <i>In vitro</i> studies have shown that caffeic acid and the discovered low-molecular-weight glow activator did not affect the light emission level of the enzyme luminescent system isolated from the mycelium of <i>N. nambi</i> in the presence of NADPH and significantly suppressed the luminescent reaction of the system induced by NADPH and hispidin. The totality of the data we obtained indicated the presence in luminous higher fungi of different biochemical pathways for the generation of visible light quanta involving different enzymes (or enzyme systems) and different substrates.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"470 - 476"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photodynamic and Plasmonic Photothermal Combination Therapy of Transplanted Tumors of a Rat Model","authors":"A. B. Bucharskaya,&nbsp;N. A. Navolokin,&nbsp;D. A. Mudrak,&nbsp;G. N. Maslyakova,&nbsp;B. N. Khlebtsov,&nbsp;N. G. Khlebtsov,&nbsp;V. D. Genin,&nbsp;E. A. Genina,&nbsp;V. V. Tuchin","doi":"10.1134/S0006350924700623","DOIUrl":"10.1134/S0006350924700623","url":null,"abstract":"<div><p>The aim of this study was to develop a combined technology of plasmon photothermal therapy and photodynamic therapy of transplanted cholangiocarcinoma PC-1 in rats. For photodynamic therapy, rats were intratumorally administered with indocyanine green diluted in polyethylene glycol at a ratio of 1 : 100 at a dose of 2 mg/kg. For plasmon photothermal therapy, gold nanorods diluted in polyethylene glycol (400 μg/mL) were intratumorally injected in a volume of 30% of the tumor volume. At 1 h after injection, the tumor was percutaneously irradiated with a diode infrared laser with a wavelength of 808 nm at a power density of 2.3 W/cm² for 15 min. The animals were removed from the experiment 72 h and 21 days after therapy. Morphological studies of the tumor were performed on sections stained with standard and immunohistochemical methods. A significant increase in tumor temperature was noted, up to 60.0 ± 4.1°C with combined plasmon photothermal and photodynamic therapy. After 72 h, pronounced necrotic changes were observed in the tumor tissue and intact tumor cells were observed only on the periphery of the tumor. At 21 days after therapy, a significant inhibition of tumor growth was noted; the inhibition index by tumor mass was 77.4%.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"559 - 565"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Underwater Measurements of Transmitted Light Spectra in Stratified Reservoirs of the White Sea Coast as a Key to the Understanding of Pigment Composition of Phototrophs in the Chemocline Zone","authors":"E. A. Labunskaya,&nbsp;D. A. Voronov,&nbsp;V. I. Lobyshev,&nbsp;E. D. Krasnova","doi":"10.1134/S000635092470060X","DOIUrl":"10.1134/S000635092470060X","url":null,"abstract":"<div><p>Measurements of the spectral composition of light at the boundary of the photic zone in seven coastal reservoirs, which are isolated from the sea to varying degrees, as well as in the marine water area and in a freshwater lake showed that in marine and brackish reservoirs, mainly green light reaches it; in lakes with a fresh upper layer it is orange, red and far-red. In meromictic reservoirs, the photic zone was limited by a colored layer of water with a massive development of phototrophic microorganisms. Their pigment composition is in good agreement with the spectral composition of transmitted light. The marine bays and lagoons were dominated by taxa with red pigments: cryptophytic algae with phycoerythrin-545, purple sulfur bacteria with okenone carotenoid, brown green sulfur bacteria with isorenieratene and bacteriochlorophyll <i>e</i>. In lakes with fresh upper water, unicellular algae and green sulfur bacteria with chlorobactene and bacteriochlorophyll <i>d</i> developed. The spectral range can serve as a selective factor that determines the composition of a community of phototrophs with structurally different antennas and similar light absorption spectra.</p></div>","PeriodicalId":493,"journal":{"name":"Biophysics","volume":"69 3","pages":"533 - 550"},"PeriodicalIF":4.033,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142859644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}