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A novel pro-apoptotic role of zinc octacarboxyphthalocyanine in melanoma me45 cancer cell's photodynamic therapy (PDT)
摘要： Zn-based phthalocyanine acts as drug or photosensitizer in photodynamic therapy (PDT) for the treatment of cancer cells. The activated zinc octacarboxyphthalocyanine (ZnPcOC) reacts with oxygen, to generate reactive oxygen species for the damage of melanoma cancer cells, Me45. This in vitro study aimed at investigating the cytotoxic effects of different concentrations of ZnPcOC activated with a diode laser (λ=685 nm) on Me45, and normal human fibroblast cells, NHDF. To perform this study 104 cells/ml were seeded in 96-well plates and allowed to attach overnight, after which cells were treated with different concentrations of ZnPcOC (10, 20 and 30 μM). After 4 h, cells were irradiated with a constant light dose of 2.5; 4.5 and 7.5 J/cm2. Post-irradiated cells were incubated for 24 h before cell viability was measured using the MTT viability assay. Data indicated that high concentrations of ZnPcOC (30 μM) in its inactive state are not cytotoxic to the melanoma cancer cells and normal fibroblasts. Moreover, the results showed that photoactivated ZnPcOC (30 μM) was able to reduce the cell viability of melanoma and fibroblast to about 50%, respectively. At this photosensitizing concentration the efficacy the treatment light dose of 2.5; 4.5 and 7.5 J/cm2 was evaluated against Me45 cells. ZnPcOC at a concentration of 30 μM activated with a light dose of 2.5; 4.5 and 7.5 J/cm2 was the most efficient for the killing of melanoma cancer cells. Melanoma cancer cells after PDT with a photosensitizing concentration of 30 μM ZnPcOC and a treatment light dose of 2.5; 4.5 and 7.5 J/cm2 showed certain pro-apoptotic characteristics, such as direct inducer (early apoptosis) and long-term inducer, also (late apoptosis). This concludes that low concentrations of ZnPcOC, activated with the appropriate light dose, can be used to induce cell death in melanoma cells via ROS-induces apoptosis pathway, what was confirmed with cytometric ROS measurements. Our in vitro study showed that ZnPcOC mediated photodynamic therapy is an effective treatment option for melanoma Me45 cancer cells. 30 μM of ZnPcOC with the treatment light dose of 2.5 J/cm2 from a LED diode laser source, with a wavelength of 685 nm, was adequate to destroy melanoma cancer cells via ROS-induced apoptosis pathway, with low killing effects on healthy NHDF normal fibroblasts.
关键词： photosensitizers,zinc octacarboxyphthalocyanine (ZnPcOC),UV-Vis spectra,pro-apoptotic activity,photodynamic therapy (PDT),reactive oxygen species (ROS),melanoma Me45 cancer cells
更新于2025-09-09 09:28:46
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Detecting intracellular thiol redox state in leukaemia and heterogeneous immune cell populations: An optimised protocol for digital flow cytometers
摘要： Flow cytometric methods for detecting and quantifying reduced intracellular thiol content using fluorescein-5-maleimide (F5M) in viable eukaryotic cells date back to 1983 (Durand and Olive [1]). There has been little development in these methodologies since that time, a period that has witnessed huge technological advances, particularly with the emergence of digital multi-parameter flow cytometric systems. Concurrent advancement in our understanding of redox regulation within eukaryotic cellular systems has also followed, whereby it is now accepted that cysteine thiols partake in redox reactions, which regulate protein activity and function (Groitl and Jakob (2014), Won et al. (2012)). Moreover, we are at the dawn of a new era in redox biology whereby the importance of 'reductive stress' in eukaryotic cellular systems is gathering momentum (Wadley et al. (2018) [4]). It is therefore critical that methods be continually advanced to better understand these concepts in more detail at the cellular level. Flow cytometry is a powerful technique that may be used for this purpose. Henceforth we have rejuvenated these methods to address modern scientific questions. In this paper, essential detail is provided on: The adaption of a protocol initially described by Durand and Olive [1] for use with modern digital flow cytometer configurations. Here we provide optimal conditions for labelling intracellular thiols with F5M for detection using digital flow cytometers. Our modifications avoid the use of methanol fixation thus preserving cell viability in single cell suspension cultures. Demonstration that flow cytometry can detect the gain and loss of reduced intracellular thiols in cells exposed to physiological doses of hydrogen peroxide mediated by glucose oxidase (Hole et al. (2013) [5]). Validation of F5M protein labelling by coupling method to confocal microscopy and downstream proteomics, thus permitting a powerful experimental platform for potential use with next generation flow cytometry e.g. CyTOF (Lin and Maecker (2018) [6]).
关键词： Fluorescein-5 maleimide,Reactive oxygen species,Oxidative stress,Reductive stress,Flow cytometry
更新于2025-09-09 09:28:46
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Automated detection of individual clove trees for yield quantification in northeastern Madagascar based on multi-spectral satellite data
摘要： There is an increasing demand for clove products, mainly dried buds and essential oil on global markets. Consequently, the importance of clove trees as a provisioning service is increasing at the local level, particularly for smallholders cultivating clove trees as cash crops. Due to limited availability of data on local production, using remote sensing-based methods to quantify today's clove production is of key interest. We estimated the clove bud yield in a study site in northeastern Madagascar by detecting individual clove trees and determining relevant production systems, including pasture and clove, clove plantation and agroforestry systems. We implemented an individual tree detection method based on two machine learning approaches. Specifically, we proposed using a circular Hough transform (CHT) for the automated detection of individual clove trees. Subsequently, we implemented a tree species classification method using a random forests (RF) classifier based on a set of features extracted for relevant trees in the above production systems. Finally, we classified and mapped different production systems. Based on the number of detected clove trees growing in a clove production system, we estimated the production system-dependent clove bud yield. Our results show that 97.9% of all reference clove trees were detected using a CHT. Classifying clove and non-clove trees resulted in a producer accuracy of 70.7% and a user accuracy of 59.2% for clove trees. The classification of the clove production systems resulted in an overall accuracy of 77.9%. By averaging different clove tree yield estimates obtained from the literature, we estimated an average total yield of approximately 575 tons/year for our 25,600 ha study area. With this approach, we demonstrate a first step towards large-scale clove bud yield estimation using remote sensing data and methodologies.
关键词： Random forest,Tree species classification,Very high-resolution satellite image,Pléiades satellite,LULC classification,Single tree detection,Circular Hough transform,Clove bud yield estimation
更新于2025-09-09 09:28:46
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Spectral Identification of Native and Non-Native Plant Species for Biodiversity Assessments
摘要： Invasive species are one of the main drivers of biodiversity loss. In the past decade, the development of environmental spectroscopy, both field spectrometers and airborne imaging spectrometers, has allowed progress in identifying individual species from remote sensing data. However, use of environmental spectroscopy for species identification needs understanding at a more fundamental level, especially the development of generalized methodologies and rules for detection and mapping, which is an area of active research today. These issues will be explored using examples from a wide range of habitats and site conditions, towards the development of a robust methodology to identify native and non-native species.
关键词： invasive species,ecosystem function,biodiversity,assessment,hyperspectral
更新于2025-09-09 09:28:46
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Identification and characterization of a core set of <scp>ROS</scp> wave‐associated transcripts involved in the systemic acquired acclimation response of Arabidopsis to excess light
摘要： Systemic acquired acclimation (SAA) plays a key role in optimizing growth and preventing damages associated with fluctuating or abrupt changes in the plant environment. To be effective, SAA has to occur at a rapid rate and depend on rapid signaling pathways that transmit signals from affected tissues to all parts of the plant. Although recent studies identified several different rapid systemic signaling pathways that could mediate SAA, very little is known about the extent of their involvement in mediating transcriptomic responses. Here we reveal that the systemic transcriptomic response of plants to excess light stress is extensive in its context and involves an early (2 minute) and transient stage of transcript expression that includes thousands of genes. This early response is dependent on the respiratory burst oxidase homolog D protein, and the function of the reactive oxygen species (ROS) wave. We further identify a core set of transcripts associated with the ROS wave and suggest that some of these transcripts are involved in linking ROS with calcium signaling. Priming of a systemic leaf to become acclimated to a particular stress during SAA involves thousands of transcripts that display a rapid and transient expression pattern driven by the ROS wave.
关键词： Arabidopsis thaliana,H2O2 signaling,systemic signaling,Reactive oxygen species (ROS) wave,Transcriptomics,light stress,MYB30,systemic acquired acclimation (SAA),WRKY
更新于2025-09-09 09:28:46
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A near-infrared spectroscopy routine for unambiguous identification of cryptic ant species
摘要： Species identification—of importance for most biological disciplines—is not always straightforward as cryptic species hamper traditional identification. Fibre-optic near-infrared spectroscopy (NIRS) is a rapid and inexpensive method of use in various applications, including the identification of species. Despite its efficiency, NIRS has never been tested on a group of more than two cryptic species, and a working routine is still missing. Hence, we tested if the four morphologically highly similar, but genetically distinct ant species Tetramorium alpestre, T. caespitum, T. impurum, and T. sp. B, all four co-occurring above 1,300 m above sea level in the Alps, can be identified unambiguously using NIRS. Furthermore, we evaluated which of our implementations of the three analysis approaches, partial least squares regression (PLS), artificial neural networks (ANN), and random forests (RF), is most efficient in species identification with our data set. We opted for a 100% classification certainty, i.e., a residual risk of misidentification of zero within the available data, at the cost of excluding specimens from identification. Additionally, we examined which strategy among our implementations, one-vs-all, i.e., one species compared with the pooled set of the remaining species, or binary-decision strategies, worked best with our data to reduce a multi-class system to a two-class system, as is necessary for PLS. Our NIRS identification routine, based on a 100% identification certainty, was successful with up to 66.7% of unambiguously identified specimens of a species. In detail, PLS scored best over all species (36.7% of specimens), while RF was much less effective (10.0%) and ANN failed completely (0.0%) with our data and our implementations of the analyses. Moreover, we showed that the one-vs-all strategy is the only acceptable option to reduce multi-class systems because of a minimum expenditure of time. We emphasise our classification routine using fibre-optic NIRS in combination with PLS and the one-vs-all strategy as a highly efficient pre-screening identification method for cryptic ant species and possibly beyond.
关键词： Random forests,Ants,Species identification tool,One-vs-all strategy,Formicidae,Neural networks,Cryptic-species complex,Partial least squares regression,Tetramorium
更新于2025-09-04 15:30:14
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Light-Induced Assembly of Metal Nanoparticles on ZnO Enhances the Generation of Charge Carriers, Reactive Oxygen Species and Antibacterial Activity
摘要： Increasing the photocatalytic activity of semiconductors by forming heterojunctions with metal improves their energy transfer efficiency and environmental remediation capabilities. However, our knowledge regarding the structure-activity relationship of semiconductor/metal hybrid nanostructures is lacking due to poor control over their physicochemical properties. Here, we report a facile way to make ZnO/metal heteronanoparticles by mixing/irradiation process of ZnO and metal nanoparticles. The resultant products provide an expedient model to explore the effects of various metal NPs on light-induced electron/hole separation, reactive oxygen species (ROS) production and antibacterial activities of ZnO NPs. Electron spin resonance spectroscopy was used to compare the effect of mixing Pt, Au, or Ag NPs at different size and concentration with ZnO NPs on light-induced electron-hole separation and ROS production. The enhancing effect of metal NPs depends on particle size, composition, and mass ratio of the metal NPs to the ZnO NPs. Smaller-sized Pt NPs are more efficient in promoting charge carrier generation and ROS production. At 5 nm, Ag NPs promoted charge carrier generation more efficiently than Pt and Au NPs, but Pt NPs promoted ROS generation more efficiently than Au and Ag NPs. These results provide valuable strategy to design the synthesis of semiconductor/metal hybrid nanostructures and easy tailoring of ROS and charge carrier production.
关键词： reactive oxygen species,photocatalytic activity,metal nanoparticles,antibacterial activity,ZnO
更新于2025-09-04 15:30:14
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Reactive Species Detection in Biology || UV–Vis Absorption and Chemiluminescence Techniques
摘要： Spectrophotometric techniques involving ultraviolet and colorimetric detection offer a convenient way of detecting reactive species (RS) formation due to the prevalence of UV-Vis spectrophotometer in research laboratories. Conventional spectrophotometric measurement of RS exploits their unique chemical reactivity with a small organic molecule and/or enzyme that has specificity to these RS where formation (or disappearance) of absorption peak/s at a particular wavelength is observed at the UV to the visible region of the electromagnetic spectrum. Direct detection of O2 from xanthine oxidase in the past involves rapid-freeze technique using electron paramagnetic resonance (EPR) spectroscopy. At the same time, spectrophotometric detection of O2 generated from xanthine oxidase/xanthine system was also employed for the investigation of the enzymatic property of superoxide dismutase (SOD) where the O2 levels were measured through reduction of ferricytochrome c, tetranitromethane, or oxidation of epinephrine to adenochrome. Several approaches have been developed since then to improve sensitivity with the use of submicromolar probe concentration thus allowing minimal interferences of the probe on the biological process being investigated. Specificity has also been improved to increase the reaction rate of probes to certain RS through synthesis of new and innovative analogues that exploit the unique chemistry between the probe and RS. Chromophore stability was also achieved through improved molecular design, optimized experimental conditions, or addition of supramolecular reagents since chromophores impart inherent thermodynamic stability as a function of its chemical structure, solvent polarity, pH, temperature, or due to presence of oxido-reductants or other reactive substances. Improved sample preparation and high-throughput analysis were also developed in order to maximize efficiency in the measurement markers of oxidative stress and determination of antioxidant capacity (AOC) of known molecules, food, biological fluid, or tissue. Therefore, spectrophotometric techniques for RS measurement have found broad application in the fields of biomedical research, clinical chemistry, plant biology, food chemistry, environmental chemistry, radiation chemistry, pharmaceuticals, toxicology, or material science to name a few, or just simply for the investigation of RS production in simple chemical systems. However, unlike the fluorescence probes, spectrophotometric as well as most applications of chemiluminescence probes do not provide spectrospatial image of the RS localization in cells, hence, one cannot deduce the site of radical production unless multiple probes and/or inhibitors are used with varying compartmentalization property (i.e., extracellular or intracellular). For example, in the investigation of radical production in cellular NADPH oxidase, several methods had been suggested such as measurement of O2 consumption, use of SOD-ferricytochrome c and horseradish peroxidase (HRP)/inhibitable probe such as Amplex Red for extracellular O2 and H2O2, respectively, and the HPLC analysis of the 2-OH-E marker for the quantification of intracellular O2.
关键词： Clinical Chemistry,Oxidative Stress,Spectrophotometric Techniques,Environmental Chemistry,Reactive Species,Antioxidant Capacity,Biomedical Research,Chemiluminescence,Superoxide Dismutase,UV-Vis Absorption
更新于2025-09-04 15:30:14
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Towards understanding the enhancement of antibacterial activity in manganese doped ZnO nanoparticles
摘要： In this work we focus on enhancing the antibacterial activity of ZnO nanoparticles by Mn doping, synthesized using a wet-chemical method. The as-obtained precursor powders were deeply investigated by thermal analyses correlated with the evolved gas analysis (TG-DTA-FT-IR) and by in situ high-temperature XRD to elucidate the thermally induced processes and to understand the manganese doped ZnO nanoparticles formation. The hexagonal wurtzite-type structure and the morphological characteristics of the thermally treated samples have been investigated by X-ray diffraction, and HRTEM. An average particle size ranging between 10 to 29 nm and a polyhedral and spherical morphology with a tendency to form aggregates were evidenced by TEM images. Optical absorption measurements reveal that the band gap of ZnO decreased from 3.19 to 2.99 eV, which confirmed the existence of Zn-O-Mn interaction. The incorporation of the Mn ions into the ZnO lattice has been studied by EPR spectroscopy and also, the generation of reactive oxygen species (ROS) has been evidenced by using the EPR coupled with the spin trapping probe technique. Here, we report that in addition to altering the crystallite size, morphology and optical absorption characteristics of ZnO, the introduction of Mn dopant also improves the antibacterial efficiency against pathogenic microorganisms, namely Escherichia coli and Bacillus cereus.
关键词： Mn doping,antibacterial activity,ZnO nanoparticles,reactive oxygen species,wet-chemical synthesis
更新于2025-09-04 15:30:14
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in a hybrid trap
摘要： We report on the production of a 41K-87Rb dual-species Bose-Einstein condensate in a hybrid trap, consisting of a magnetic quadrupole and an optical dipole potential. After loading both atomic species in the trap, we cool down 87Rb first by magnetic and then by optical evaporation, while 41K is sympathetically cooled by elastic collisions with 87Rb. We eventually produce two-component condensates with more than 105 atoms and tunable species population imbalance. We observe the immiscibility of the quantum mixture by measuring the density profile of each species after releasing them from the trap.
关键词： Bose-Einstein condensate,immiscibility,hybrid trap,dual-species,sympathetic cooling
更新于2025-09-04 15:30:14